subject:"Re\: The size of the universe"



On Saturday, June 27, 2020 at 4:12:22 PM UTC-5 Brent wrote:

>
>
> On 6/27/2020 1:32 PM, Philip Thrift wrote:
>
>
> In any case, teleportation in quantum computers gives a better picture of 
> the phenomenon.
>
>
> https://www.oreilly.com/library/view/programming-quantum-computers/9781492039679/ch04.html
>
> "In this chapter we introduce a QPU program allowing us to immediately 
> teleport an object across a distance of 3.1 millimeters! The same code 
> would work *over interstellar distances*, given the right equipment."
>
>
> But not faster than light. 
>
> Brent
>



That may be an interesting comment, but does that matter to (quantum 
computer) programmers?

*They want to see their programs work.*

"The same code would work *over interstellar distances*, given the right 
equipment."

(There are 2 programmers, with programmer Alice at computer screen A on 
Earth and programmer Bob at computer screen B on Mars.)

// Example 4-1. Teleport and verify

include "qelib1.inc";
qreg q[5];
creg c[5];

// Step 1: Create an entangled pair
h q[2];
cx q[2],q[4];
barrier q[0],q[1],q[2],q[3],q[4];

// Step 2: Prepare a payload
x q[0];
h q[0];
t q[0];
barrier q[0],q[1],q[2],q[3],q[4];

// Step 3: Send
h q[0];
h q[2];
cx q[2],q[0];
h q[2];
measure q[0] -> c[0];
measure q[2] -> c[2];
barrier q[3],q[4];

// Step 4: Receive
x q[4];
z q[4];
barrier q[3],q[4];

// Step 5: Verify
tdg q[4];
h q[4];
x q[4];
measure q[4] -> c[4];



@philipthrift 

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Re: The size of the universe

2020-06-27 Thread 'Brent Meeker' via Everything List

On 6/27/2020 1:32 PM, Philip Thrift wrote:

On Saturday, June 27, 2020 at 3:21:02 PM UTC-5 Brent wrote:

On 6/27/2020 12:54 PM, Philip Thrift wrote:

On Saturday, June 27, 2020 at 2:34:58 PM UTC-5 Brent wrote:

On 6/27/2020 11:53 AM, Philip Thrift wrote:
>> The instantaneous correlations of
>> quantum entanglement cannot be used to
>> transmit information because the result
>> at each end is random.
>> Brent
> Correlation:
>
> the results at the two ends are stochastcally *dependent*
>
> not
>
> the results at the two ends are stochastcally independent.
>
> (That's what correlated means.)

And your point is?

Brent

You wrote "the result at each end is random".

But random can be

(A) stochastically independent, or
(B) stochastically dependent

It isn't clear by what type of "random" you are referring to in
your sentence.

I referred to them as "the instantaneous /*correlations */of
quantum entanglement", so I was quite explicit that they are not
statistically independent.

Brent

In any case, teleportation in quantum computers gives a better picture 
of the phenomenon.

https://www.oreilly.com/library/view/programming-quantum-computers/9781492039679/ch04.html

"In this chapter we introduce a QPU program allowing us to immediately 
teleport an object across a distance of 3.1 millimeters! The same code 
would work *over interstellar distances*, given the right equipment."

But not faster than light.

Brent

 @philipthrift

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Re: The size of the universe



On Saturday, June 27, 2020 at 3:21:02 PM UTC-5 Brent wrote:

>
>
> On 6/27/2020 12:54 PM, Philip Thrift wrote:
>
>
>
> On Saturday, June 27, 2020 at 2:34:58 PM UTC-5 Brent wrote:
>
>>
>>
>> On 6/27/2020 11:53 AM, Philip Thrift wrote: 
>> >> The instantaneous correlations of 
>> >> quantum entanglement cannot be used to 
>> >> transmit information because the result 
>> >> at each end is random. 
>> >> Brent 
>> > Correlation: 
>> > 
>> > the results at the two ends are stochastcally *dependent* 
>> > 
>> > not 
>> > 
>> > the results at the two ends are stochastcally independent. 
>> > 
>> > (That's what correlated means.) 
>>
>> And your point is? 
>>
>> Brent 
>>
>
>
>
> You wrote "the result at each end is random".  
>
> But random can be 
>
> (A) stochastically independent, or
> (B) stochastically dependent
>
> It isn't clear by what type of "random" you are referring to in your 
> sentence.
>
>
> I referred to them as "the instantaneous *correlations *of quantum 
> entanglement", so I was quite explicit that they are not statistically 
> independent.
>
> Brent
>




In any case, teleportation in quantum computers gives a better picture of 
the phenomenon.

https://www.oreilly.com/library/view/programming-quantum-computers/9781492039679/ch04.html

"In this chapter we introduce a QPU program allowing us to immediately 
teleport an object across a distance of 3.1 millimeters! The same code 
would work *over interstellar distances*, given the right equipment."
 @philipthrift



>

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Re: The size of the universe

2020-06-27 Thread 'Brent Meeker' via Everything List




On 6/27/2020 12:54 PM, Philip Thrift wrote:



On Saturday, June 27, 2020 at 2:34:58 PM UTC-5 Brent wrote:



On 6/27/2020 11:53 AM, Philip Thrift wrote:
>> The instantaneous correlations of
>> quantum entanglement cannot be used to
>> transmit information because the result
>> at each end is random.
>> Brent
> Correlation:
>
> the results at the two ends are stochastcally *dependent*
>
> not
>
> the results at the two ends are stochastcally independent.
>
> (That's what correlated means.)

And your point is?

Brent




Y9u wrote "the result at each end is random".

But random can be

(A) stochastically independent, or
(B) stochastically dependent

It isn't clear by what type of "random" you are referring to in your 
sentence.


I referred to them as "the instantaneous /*correlations */of quantum 
entanglement", so I was quite explicit that they are not statistically 
independent.


Brent


Is it (A) or (B)?

Makes a world of difference.

@philipthrift



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Re: The size of the universe



On Saturday, June 27, 2020 at 2:34:58 PM UTC-5 Brent wrote:

>
>
> On 6/27/2020 11:53 AM, Philip Thrift wrote: 
> >> The instantaneous correlations of 
> >> quantum entanglement cannot be used to 
> >> transmit information because the result 
> >> at each end is random. 
> >> Brent 
> > Correlation: 
> > 
> > the results at the two ends are stochastcally *dependent* 
> > 
> > not 
> > 
> > the results at the two ends are stochastcally independent. 
> > 
> > (That's what correlated means.) 
>
> And your point is? 
>
> Brent 
>



Y9u wrote "the result at each end is random".  

But random can be 

(A) stochastically independent, or
(B) stochastically dependent

It isn't clear by what type of "random" you are referring to in your 
sentence.

Is it (A) or (B)?

Makes a world of difference.

@philipthrift



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Re: The size of the universe

2020-06-27 Thread 'Brent Meeker' via Everything List





On 6/27/2020 11:53 AM, Philip Thrift wrote:

The instantaneous correlations of
quantum entanglement cannot be used to
transmit information because the result
at each end is random.
Brent

Correlation:

the resuls at the two ends are stochastcally *dependent*

not

the results at the two ends are stochastcally independent.

(That's what correlated means.)


And your point is?

Brent

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Re: The size of the universe



https://www.oreilly.com/library/view/programming-quantum-computers/9781492039679/ch04.html

"In this chapter we introduce a QPU program allowing us to immediately teleport 
an object across a distance of 3.1 millimeters! The same code would work over 
interstellar distances, given the right equipment."

@philipthrift 

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Re: The size of the universe

>The instantaneous correlations of 
> quantum entanglement cannot be used to 
> transmit information because the result
> at each end is random.

> Brent

Correlation:

the resuls at the two ends are stochastcally *dependent*

not

the results at the two ends are stochastcally independent.

(That's what correlated means.)


@philipthrift 

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Re: The size of the universe

2020-06-27 Thread 'Brent Meeker' via Everything List

The instantaneous correlations of quantum entanglement cannot be used to 
transmit information because the result at each end is random.


Brent

On 6/27/2020 10:31 AM, spudboy100 via Everything List wrote:
So, based on this paper, sorry to tell you, that, at least 
conceptually, it makes now plausible things that spring to mind, the 
science fictional, as well as the religious. Is the is the intent of 
the authors-can I hear, a "hell no," from the choir? This is just my 
observation that when you see what looks like the instantaneous 
movement of information, (it cannot be correct can it?) topics become 
more interesting. Thanks.



-Original Message-
From: Philip Thrift 
To: Everything List 
Sent: Sat, Jun 27, 2020 5:57 am
Subject: Re: The size of the universe



On Friday, June 26, 2020 at 8:19:08 PM UTC-5 Brent wrote:


https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.124.251302

Brent




Interesting.

/As a consequence, this theory propagates information instantaneously 
everywhere in space-time. This is not surprising as causality in a 
relativistic theory demands the presence of a negative frequency mode 
(“antiparticle”) //, which is precisely what gives rise to the poles 
at physical momenta./

/
/

@philipthrift
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Re: The size of the universe

2020-06-27 Thread spudboy100 via Everything List

So, based on this paper, sorry to tell you, that, at least conceptually, it 
makes now plausible things that spring to mind, the science fictional, as well 
as the religious. Is the is the intent of the authors-can I hear, a "hell no," 
from the choir? This is just my observation that when you see what looks like 
the instantaneous movement of information, (it cannot be correct can it?) 
topics become more interesting. Thanks. 


-Original Message-
From: Philip Thrift 
To: Everything List 
Sent: Sat, Jun 27, 2020 5:57 am
Subject: Re: The size of the universe



On Friday, June 26, 2020 at 8:19:08 PM UTC-5 Brent wrote:


 https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.124.251302
 
 Brent




Interesting.
As a consequence, this theory propagates information instantaneously everywhere 
in space-time. This is not surprising as causality in a relativistic theory 
demands the presence of a negative frequency mode (“antiparticle”) , which is 
precisely what gives rise to the poles at physical momenta.

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Re: The size of the universe

On Friday, June 26, 2020 at 8:19:08 PM UTC-5 Brent wrote:

>
> https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.124.251302
>
> Brent
>

Interesting.

*As a consequence, this theory propagates information instantaneously 
everywhere in space-time. This is not surprising as causality in a 
relativistic theory demands the presence of a negative frequency mode 
(“antiparticle”) **, which is precisely what gives rise to the poles at 
physical momenta.*

@philipthrift

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Re: The size of the universe

2020-06-26 Thread 'Brent Meeker' via Everything List

On 6/13/2020 4:30 PM, Bruce Kellett wrote:
On Sun, Jun 14, 2020 at 3:54 AM smitra > wrote:

On 13-06-2020 02:57, Bruce Kellett wrote:
>
>> My point is that your arguments are
>> totally flawed. You stated that a free field theory is analogous to
>> aset of independent harmonic oscillators in real space, which is
>> nonsenseas they are coupled via the (nabla phi)^2 term, it's
only in k-space
>> that you have independent oscillators.
>
> Momentum space and position space are related by a Fourier
transform.
> Are you claiming that a Fourier transform violates the conservation
> laws?

By taking the Fourier transform to decouple the osscilators, you
are no
longer considering the local energy. Your argument was that because a
free field theory is basically the same as a collection of
noninteracting SHOs, the fact that energy is conserved means that
there
cannot be local fluctuations. But each such independent SHO in
k-space
isn't localized in real space. In real space the oscillators are
coupled
by the (nabla phi)^2 term and local energy momentum conservation does
invilve a transfer of energy and momentum from one oscillator to
another.

There seems to be something wrong with this. QFT is equivalent to a 
picture in which there are independent SHOs at every point in space. 
If these are all in their lowest energy state, then the field is in 
its lowest energy state. Excitation of one or more of the oscillators 
corresponds to the presence of more energy (and particles). The higher 
energy configuration can be analysed in terms of the modes, which are 
the plane waves of determinate wavelength. If you start with a smooth 
field with all the oscillators in their ground state, this lowest 
energy configuration persists until some energy is added from somewhere.

A simple analogy can be given in terms of the surface of a body of 
water, such as a lake or the sea. If there is a "mirror calm", the 
surface is completely smooth, and we have the state of lowest energy. 
This will persist until some energy is added, say from the wind. This 
can cause ripples which, once formed, will persist in the absence of a 
driving force until friction dissipates the energy as heat. Adding 
more energy results in bigger waves, until we can have the massive 
energy input that is seen in storms.

The lesson I am trying to draw is that ripples on the surface of a 
lake (waves) cannot arise spontaneously -- they require some energy 
input, say from the coupling of the wind with the surface of the 
water. The same is true in inflation. You start off with a uniformly 
smooth (classical) inflaton field, with the same energy everywhere. 
Variations in the field, or variations in local energy density, cannot 
arise spontaneously, they require some energy input from outside. 
Since quantum fluctuations are assumed to be internal to the field, 
they cannot add this required energy, so the variations in energy 
density cannot arise from quantum fluctuations. Quantum fluctuations, 
insofar as these exist as disconnected Feynman loops, do not have any 
energy, and do not contribute to any physical effects.

In the Wikipedia article on quantum fluctuations, these fluctuations 
are said to be a temporary change in the amount of energy at a point 
in space as explained in the HUP. This is, of course, nonsense, since 
the uncertainty principle does not suggest any such thing. The 
time-energy form of the UP:

Delta-t*Delta-E >= hbar/2,

is an inequality. The normal story is that this allows a particle to 
"borrow" and amount of energy Delta-E from the vacuum provided it pays 
this amount back in the time allowed by the UP. Unfortunately, the 
inequality is in the wrong direction for this to make sense. If we 
"borrow" and amount of energy Delta-E, the the UP says that the 
uncertainty in time (the time within which the energy must be paid 
back) is

 Delta-t  >=  hbar/(2*Delta-E).

Which means that Delta-t is unbounded above -- it can take on any 
arbitrarily large value and still be consistent with the UP. If true, 
this would mean that energy conservation is impossible (since the 
vacuum could randomly fluctuate into states of arbitrarily high energy 
that persisted for arbitrarily long times.) This is contrary to 
observation, so one of the input assumptions must be wrong. The only 
relevant input assumption (apart from the UP) is that "borrowing" 
energy from the vacuum makes sense. Since such an assumption leads to 
results in manifest contradiction with experience, the assumption must 
be wrong.

Consequently, the usual mythology about quantum fluctuations is not true.

So quantum fluctuations cannot cause spatial variations in the field.

False, this doesn't follow from the above. Also it the opposite
has been
demonstrated in a massive body of literature on this subject to which

Re: The size of the universe

2020-06-25 Thread Bruce Kellett

On Fri, Jun 26, 2020 at 12:25 PM smitra  wrote:

> On 26-06-2020 03:24, Bruce Kellett wrote:
> > On Fri, Jun 26, 2020 at 9:31 AM smitra  wrote:
> >
> >> On 14-06-2020 01:30, Bruce Kellett wrote:
> >>>
> >>> There seems to be something wrong with this. QFT is equivalent to a
> >>> picture in which there are independent SHOs at every point in space.
> >>
> >> This is false, the SHO are only independent in momentum space, not in
> >> real space where they are coupled via the (nabla phi)^2 term which leads
> >> to nontrivial spatial correlations.
> >
> > The (nabla phi)^2 term does not get you energy fluctuations. As I
> > understand it, we imagine an independent SHO for each mode (k value,
> > or energy) at every spacetime point.
>
> > For each mode separately, these
> > oscillators are coupled, basically because a momentum eigenstate
> > (single value of k, or single mode) is a plane wave over all space.
> > But because the modes are not coupled to each other, there can be no
> > fluctuations of energy. A real field value is a superposition of
> > independent modes (independent degrees of freedom).
>
> That energy is not located, so you can end up with non-smooth energy
> distribution.
>


Plane waves have the same energy everywhere. The superpositions of modes
that would be required to get a non-smooth energy distribution cannot arise
spontaneously.

>> Where else would the propagator of
> >> the free field theory come from if is weren't for this term?
> >
> > The free-field propagator comes from the Green's function
> > corresponding to the creation of a particle at one point and its
> > annihilation at some other point. When one does a perturbation
> > expansion of this Green's function (in terms of Feynman graphs, for
> > instance), there are coupled terms, corresponding to the tree diagram
> > plus corrections,  and the so-called vacuum "fluctuations", which are
> > the non-coupled diagrams to all orders. These non coupled diagrams are
> > all of strictly zero net energy, and contribute at most an overall
> > phase to the amplitude. In no circumstances does any of this give rise
> > to conservation-violating "energy fluctuations".
>
> Total energy is conserved, that doesn't mean that there cannot be local
> fluctuations.
>


This physics is local, with local energy conservation, so your statement is
absurd. Show me the Feynman diagram that violates energy conservation!

>>> If these are all in their lowest energy state, then the field is in
> >>> its lowest energy state. Excitation of one or more of the oscillators
> >>> corresponds to the presence of more energy (and particles). The higher
> >>> energy configuration can be analysed in terms of the modes, which are
> >>> the plane waves of determinate wavelength. If you start with a smooth
> >>> field with all the oscillators in their ground state, this lowest
> >>> energy configuration persists until some energy is added from
> >>> somewhere.
> >>>
> >>>
> >>> Consequently, the usual mythology about quantum fluctuations is not
> >>> true.
> >>>
> >>
> >> While it is true that reasoning based on uncertainty principle are not
> >> rigorously correct, they are only used to illustrate the effect
> >> qualitatively.
> >
> > The trouble is that such heuristics are generally the only motivation
> > given for the introduction of "fluctuations" . One paper I saw
> > recently went so far as to say that it involved the exchange of
> > virtual photons, which could only travel as far as allowed by the UP
> > limit on their lifetime. It is nonsense like this that should be
> > stamped out. If there is a rigorous derivation of energy-violating
> > "quantum fluctuations", then I have yet to see it -- such terms do not
> > arise in the conventional perturbation approach to QFT.
> >
> >> The theory as published in the literature is based on
> >> rigorous treatment based on standard QFT.
> >>
>  So quantum fluctuations cannot cause spatial variations in the field.
> 
>  False, this doesn't follow from the above. Also it the opposite has
> been
>  demonstrated in a massive body of literature on this subject to which
>  thousands of experts who are all extremely well versed in QFT have
>  contributed to.
> >>>
> >>> Can you point me to some recent key papers?
> >>
> >> See e.g. here:
> >>
> >> https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.251302
> >
> > This does not give anything rigorous for the origin of fluctuations,
> > it simply compares and contrasts two possibilities in the context of
> > inflation.
> >
> > Bruce
>
> Recent articles will not publish a rigorous derivation, you need to read
> the cited references and then perhaps the cited references in those
> articles to get to the original articles that date back from the early
> 1980s.



In other words, you do not have any idea how to make this rigorous either.

But the fact that there are two possibilities according to the
> experts in the field, shows that your argument

Re: The size of the universe

2020-06-25 Thread smitra

On 26-06-2020 03:24, Bruce Kellett wrote:

On Fri, Jun 26, 2020 at 9:31 AM smitra wrote:

On 14-06-2020 01:30, Bruce Kellett wrote:

There seems to be something wrong with this. QFT is equivalent to

picture in which there are independent SHOs at every point in

space.

This is false, the SHO are only independent in momentum space, not
in
real space where they are coupled via the (nabla phi)^2 term which
leads
to nontrivial spatial correlations.

The (nabla phi)^2 term does not get you energy fluctuations. As I
understand it, we imagine an independent SHO for each mode (k value,
or energy) at every spacetime point.

For each mode separately, these
oscillators are coupled, basically because a momentum eigenstate
(single value of k, or single mode) is a plane wave over all space.
But because the modes are not coupled to each other, there can be no
fluctuations of energy. A real field value is a superposition of
independent modes (independent degrees of freedom).

That energy is not located, so you can end up with non-smooth energy
distribution.

Where else would the propagator of
the free field theory come from if is weren't for this term?

The free-field propagator comes from the Green's function
corresponding to the creation of a particle at one point and its
annihilation at some other point. When one does a perturbation
expansion of this Green's function (in terms of Feynman graphs, for
instance), there are coupled terms, corresponding to the tree diagram
plus corrections, and the so-called vacuum "fluctuations", which are
the non-coupled diagrams to all orders. These non coupled diagrams are
all of strictly zero net energy, and contribute at most an overall
phase to the amplitude. In no circumstances does any of this give rise
to conservation-violating "energy fluctuations".

Total energy is conserved, that doesn't mean that there cannot be local
fluctuations.

If these are all in their lowest energy state, then the field is

its lowest energy state. Excitation of one or more of the

oscillators

corresponds to the presence of more energy (and particles). The

higher

energy configuration can be analysed in terms of the modes, which

are

the plane waves of determinate wavelength. If you start with a

smooth

field with all the oscillators in their ground state, this lowest
energy configuration persists until some energy is added from
somewhere.

Consequently, the usual mythology about quantum fluctuations is

not

true.

While it is true that reasoning based on uncertainty principle are
not
rigorously correct, they are only used to illustrate the effect
qualitatively.

The trouble is that such heuristics are generally the only motivation
given for the introduction of "fluctuations" . One paper I saw
recently went so far as to say that it involved the exchange of
virtual photons, which could only travel as far as allowed by the UP
limit on their lifetime. It is nonsense like this that should be
stamped out. If there is a rigorous derivation of energy-violating
"quantum fluctuations", then I have yet to see it -- such terms do not
arise in the conventional perturbation approach to QFT.

The theory as published in the literature is based on
rigorous treatment based on standard QFT.

So quantum fluctuations cannot cause spatial variations in the

field.

False, this doesn't follow from the above. Also it the opposite

has been

demonstrated in a massive body of literature on this subject to

which

thousands of experts who are all extremely well versed in QFT

have

contributed to.

Can you point me to some recent key papers?

See e.g. here:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.251302

This does not give anything rigorous for the origin of fluctuations,
it simply compares and contrasts two possibilities in the context of
inflation.

Bruce

Recent articles will not publish a rigorous derivation, you need to read
the cited references and then perhaps the cited references in those
articles to get to the original articles that date back from the early
1980s. But the fact that there are two possibilities according to the
experts in the field, shows that your argument is wrong (because it is
elementary, if it were correct it would have been noted very early on in
the development of inflation theory and no one in that field would
invoke quantum fluctuations as a possible source of density
fluctuation).

Saibal

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[1].

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Re: The size of the universe

2020-06-25 Thread Bruce Kellett

On Fri, Jun 26, 2020 at 9:31 AM smitra  wrote:

> On 14-06-2020 01:30, Bruce Kellett wrote:
> >
> > There seems to be something wrong with this. QFT is equivalent to a
> > picture in which there are independent SHOs at every point in space.
>
> This is false, the SHO are only independent in momentum space, not in
> real space where they are coupled via the (nabla phi)^2 term which leads
> to nontrivial spatial correlations.

The (nabla phi)^2 term does not get you energy fluctuations. As I
understand it, we imagine an independent SHO for each mode (k value, or
energy) at every spacetime point. For each mode separately, these
oscillators are coupled, basically because a momentum eigenstate (single
value of k, or single mode) is a plane wave over all space. But because the
modes are not coupled to each other, there can be no fluctuations of
energy. A real field value is a superposition of independent modes
(independent degrees of freedom).

Where else would the propagator of
> the free field theory come from if is weren't for this term?
>

The free-field propagator comes from the Green's function corresponding to
the creation of a particle at one point and its annihilation at some other
point. When one does a perturbation expansion of this Green's function (in
terms of Feynman graphs, for instance), there are coupled terms,
corresponding to the tree diagram plus corrections,  and the so-called
vacuum "fluctuations", which are the non-coupled diagrams to all orders.
These non coupled diagrams are all of strictly zero net energy, and
contribute at most an overall phase to the amplitude. In no circumstances
does any of this give rise to conservation-violating "energy fluctuations".

> > If these are all in their lowest energy state, then the field is in
> > its lowest energy state. Excitation of one or more of the oscillators
> > corresponds to the presence of more energy (and particles). The higher
> > energy configuration can be analysed in terms of the modes, which are
> > the plane waves of determinate wavelength. If you start with a smooth
> > field with all the oscillators in their ground state, this lowest
> > energy configuration persists until some energy is added from
> > somewhere.
> >
>
> >
> > Consequently, the usual mythology about quantum fluctuations is not
> > true.
> >
>
> While it is true that reasoning based on uncertainty principle are not
> rigorously correct, they are only used to illustrate the effect
> qualitatively.

The trouble is that such heuristics are generally the only motivation given
for the introduction of "fluctuations" . One paper I saw recently went so
far as to say that it involved the exchange of virtual photons, which could
only travel as far as allowed by the UP limit on their lifetime. It is
nonsense like this that should be stamped out. If there is a rigorous
derivation of energy-violating "quantum fluctuations", then I have yet to
see it -- such terms do not arise in the conventional perturbation approach
to QFT.

The theory as published in the literature is based on
> rigorous treatment based on standard QFT.
>
> >> So quantum fluctuations cannot cause spatial variations in the field.
> >>
> >> False, this doesn't follow from the above. Also it the opposite has been
> >> demonstrated in a massive body of literature on this subject to which
> >> thousands of experts who are all extremely well versed in QFT have
> >> contributed to.
> >
> > Can you point me to some recent key papers?
>
> See e.g. here:
>
> https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.251302

This does not give anything rigorous for the origin of fluctuations, it
simply compares and contrasts two possibilities in the context of inflation.

Bruce

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Re: The size of the universe

2020-06-25 Thread smitra


On 14-06-2020 01:30, Bruce Kellett wrote:

On Sun, Jun 14, 2020 at 3:54 AM smitra  wrote:


On 13-06-2020 02:57, Bruce Kellett wrote:



My point is that your arguments are
totally flawed. You stated that a free field theory is analogous

to

a set of independent harmonic oscillators in real space, which is
nonsense as they are coupled via the (nabla phi)^2 term, it's

only in k-space

that you have independent oscillators.


Momentum space and position space are related by a Fourier

transform.

Are you claiming that a Fourier transform violates the

conservation

laws?


By taking the Fourier transform to decouple the osscilators, you are
no
longer considering the local energy. Your argument was that because
a
free field theory is basically the same as a collection of
noninteracting SHOs, the fact that energy is conserved means that
there
cannot be local fluctuations. But each such independent SHO in
k-space
isn't localized in real space. In real space the oscillators are
coupled
by the (nabla phi)^2 term and local energy momentum conservation
does
invilve a transfer of energy and momentum from one oscillator to
another.


There seems to be something wrong with this. QFT is equivalent to a
picture in which there are independent SHOs at every point in space.


This is false, the SHO are only independent in momentum space, not in 
real space where they are coupled via the (nabla phi)^2 term which leads 
to nontrivial spatial correlations. Where else would the propagator of 
the free field theory come from if is weren't for this term?



If these are all in their lowest energy state, then the field is in
its lowest energy state. Excitation of one or more of the oscillators
corresponds to the presence of more energy (and particles). The higher
energy configuration can be analysed in terms of the modes, which are
the plane waves of determinate wavelength. If you start with a smooth
field with all the oscillators in their ground state, this lowest
energy configuration persists until some energy is added from
somewhere.

A simple analogy can be given in terms of the surface of a body of
water, such as a lake or the sea. If there is a "mirror calm", the
surface is completely smooth, and we have the state of lowest energy.
This will persist until some energy is added, say from the wind. This
can cause ripples which, once formed, will persist in the absence of a
driving force until friction dissipates the energy as heat. Adding
more energy results in bigger waves, until we can have the massive
energy input that is seen in storms.

The lesson I am trying to draw is that ripples on the surface of a
lake (waves) cannot arise spontaneously -- they require some energy
input, say from the coupling of the wind with the surface of the
water. The same is true in inflation. You start off with a uniformly
smooth (classical) inflaton field, with the same energy everywhere.
Variations in the field, or variations in local energy density, cannot
arise spontaneously, they require some energy input from outside.
Since quantum fluctuations are assumed to be internal to the field,
they cannot add this required energy, so the variations in energy
density cannot arise from quantum fluctuations. Quantum fluctuations,
insofar as these exist as disconnected Feynman loops, do not have any
energy, and do not contribute to any physical effects.

In the Wikipedia article on quantum fluctuations, these fluctuations
are said to be a temporary change in the amount of energy at a point
in space as explained in the HUP. This is, of course, nonsense, since
the uncertainty principle does not suggest any such thing. The
time-energy form of the UP:

Delta-t*Delta-E >= hbar/2,

is an inequality. The normal story is that this allows a particle to
"borrow" and amount of energy Delta-E from the vacuum provided it pays
this amount back in the time allowed by the UP. Unfortunately, the
inequality is in the wrong direction for this to make sense. If we
"borrow" and amount of energy Delta-E, the the UP says that the
uncertainty in time (the time within which the energy must be paid
back) is

 Delta-t  >=  hbar/(2*Delta-E).

Which means that Delta-t is unbounded above -- it can take on any
arbitrarily large value and still be consistent with the UP. If true,
this would mean that energy conservation is impossible (since the
vacuum could randomly fluctuate into states of arbitrarily high energy
that persisted for arbitrarily long times.) This is contrary to
observation, so one of the input assumptions must be wrong. The only
relevant input assumption (apart from the UP) is that "borrowing"
energy from the vacuum makes sense. Since such an assumption leads to
results in manifest contradiction with experience, the assumption must
be wrong.

Consequently, the usual mythology about quantum fluctuations is not
true.



While it is true that reasoning based on uncertainty principle are not 
rigorously correct, they are only used to illustrate the

Re: The size of the universe

2020-06-16 Thread Alan Grayson



On Monday, June 15, 2020 at 10:54:08 AM UTC-6, Alan Grayson wrote:
>
>
>
> On Saturday, June 13, 2020 at 5:53:27 AM UTC-6, Alan Grayson wrote:
>>
>>
>>
>> On Thursday, June 11, 2020 at 7:31:18 PM UTC-6, Bruce wrote:
>>>
>>> On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:
>>>
 On 11-06-2020 02:01, Bruce Kellett wrote:

 > Energy and momentum are conserved locally, even in GR where global
 > energy conservation fails in a non-static universe.

 Not in the sense you are suggesting. Energy and momentum are constant 
 in 
 a closed volume and one can then write down the conservation law in a 
 local form. But this so-called "local conservation of energy and 
 momentum" does not mean that it's conserved in the sense of having a 
 constant value everywhere.

>>>
>>>
>>> Bullshit. Energy-momentum conservation comes from translational 
>>> invariance of the Lagrangian in space and time. Local conservation is 
>>> ensured in GR by the vanishing of the covariant derivative of the 
>>> Stress-Energy tensor. Local in this sense means on the scale of the galaxy 
>>> or more. In the absence of a time-like Killing vector in an expanding 
>>> universe, this conservation breaks down on larger scales, such as the scale 
>>> of the Hubble expansion.
>>>
>>> If you have a theory that violates local energy-momentum conservation in 
>>> the above sense, then your theory is wrong. Local conservation does not 
>>> mean that energy necessarily has the same constant value everywhere.
>>>
>>> .
>>>
 >> The expectation value of these energies do fluctuate.
 > 
 > You can introduce coupled harmonic oscillators, but that is not how
 > you form a quantized field theory. Such fluctuations arise from
 > non-local couplings -- they are not fluctuations of the original
 > quantum field. Energy-momentum is locally conserved, even in GR and an
 > expanding universe.
 > 

 The Casimir effect, the effective negative pressure of the vacuum is 
 another way to see that your arguments based on local energy 
 conservation are wrong. Vacuum fluctuations in the local energy density 
 do exist and they have measurable effects.

>>>
>>>
>>> I wondered when this would come up. It is always the last resort of 
>>> those who contend that vacuum fluctuations in local energy densities are 
>>> real. I remember reading a comprehensive review of the Casimir effect in a 
>>> scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did 
>>> not keep a reference, and I have been unable to find this paper again. But 
>>> I do remember the main points of the analysis: They discuss the 
>>> Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of 
>>> supposed vacuum fluctuations, but they dismiss this approach as 
>>> insufficiently general. They give a detailed account of the Casimir effect 
>>> in terms of generalized van der Waals forces. The reason for preferring 
>>> this explanation (over vacuum fluctuations, sidestepping the question of 
>>> whether these fluctuations exist or not)  is that the van der Waals 
>>> explanation extends seamlessly to the Casimir effect between irregular 
>>> surfaces -- indeed, to the attractive force between a point and a plane 
>>> surface -- where the fluctuation model is silent.
>>>
>>> Bruce
>>>
>>
>> *I'd like to do a search for this paper. Perhaps you can give me some 
>> information, even approximate, in order to find it, such as approximate 
>> name, author or authors, approximate date of publication, and anything else 
>> you can recall. TIA, AG *
>>
>
> *To put it as politely as possible, and undeservedly so, why must ethical 
> challenges, yours, be part of this picture? AG *
>

*OK; I finally get it. I really get it. At the core, at YOUR core, is a 
rude, anally retentive scum-bucket. I am NOT asking much; just any 
additional information you might recall, that could aid in my search of the 
important article you referenced. But that's just TOO much for you, and I 
now know why. So please; do me a favor; go fuck yourself if you can figure 
out how.  AG *

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Re: The size of the universe



On Monday, June 15, 2020 at 6:11:16 PM UTC-6, Alan Grayson wrote:
>
>
>
> On Monday, June 15, 2020 at 5:03:46 PM UTC-6, Alan Grayson wrote:
>>
>>
>>
>> On Monday, June 15, 2020 at 4:27:35 PM UTC-6, Bruce wrote:
>>>
>>> On Tue, Jun 16, 2020 at 2:50 AM Alan Grayson  
>>> wrote:
>>>
 On Saturday, June 13, 2020 at 5:30:15 PM UTC-6, Bruce wrote:
>
>
> Consequently, the usual mythology about quantum fluctuations is not 
> true.
>

 *But isn't there factually undeniable, empirical evidence that if one 
 repeatedly measures the vacuum energy at some position in space, it 
 changes, aka "fluctuates"?  AG*

>>>
>>>
>>> What factually undeniable evidence? How do you measure the vacuum energy 
>>> at a point?
>>>
>>
>> *I don't know how vacuum energy is measured. But there are values given 
>> for it, so there must be methods to measure it, unless it's all a con-job. 
>> AG *
>>
>
> *The vacuum energy has a specific measured value, namely the value of the 
> cosmological constant. I have no idea how it's measured. AG*
>

*But however it's measured, it fluctuates around some mean value. So the 
question is whether the fluctuation is classical or quantum, and there 
seems to be no way within, say, QED, for the ground state energies to 
fluctuate quantum mechanically. AG *

>
>>> Bruce
>>>
>>

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Re: The size of the universe



On Monday, June 15, 2020 at 5:03:46 PM UTC-6, Alan Grayson wrote:
>
>
>
> On Monday, June 15, 2020 at 4:27:35 PM UTC-6, Bruce wrote:
>>
>> On Tue, Jun 16, 2020 at 2:50 AM Alan Grayson  wrote:
>>
>>> On Saturday, June 13, 2020 at 5:30:15 PM UTC-6, Bruce wrote:


 Consequently, the usual mythology about quantum fluctuations is not 
 true.

>>>
>>> *But isn't there factually undeniable, empirical evidence that if one 
>>> repeatedly measures the vacuum energy at some position in space, it 
>>> changes, aka "fluctuates"?  AG*
>>>
>>
>>
>> What factually undeniable evidence? How do you measure the vacuum energy 
>> at a point?
>>
>
> *I don't know how vacuum energy is measured. But there are values given 
> for it, so there must be methods to measure it, unless it's all a con-job. 
> AG *
>

*The vacuum energy has a specific measured value, namely the value of the 
cosmological constant. I have no idea how it's measured. AG*

>
>> Bruce
>>
>

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Re: The size of the universe



On Monday, June 15, 2020 at 4:27:35 PM UTC-6, Bruce wrote:
>
> On Tue, Jun 16, 2020 at 2:50 AM Alan Grayson  > wrote:
>
>> On Saturday, June 13, 2020 at 5:30:15 PM UTC-6, Bruce wrote:
>>>
>>>
>>> Consequently, the usual mythology about quantum fluctuations is not true.
>>>
>>
>> *But isn't there factually undeniable, empirical evidence that if one 
>> repeatedly measures the vacuum energy at some position in space, it 
>> changes, aka "fluctuates"?  AG*
>>
>
>
> What factually undeniable evidence? How do you measure the vacuum energy 
> at a point?
>

*I don't know how vacuum energy is measured. But there are values given for 
it, so there must be methods to measure it, unless it's all a con-job. AG *

>
> Bruce
>

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Re: The size of the universe

2020-06-15 Thread Bruce Kellett

On Tue, Jun 16, 2020 at 2:50 AM Alan Grayson  wrote:

> On Saturday, June 13, 2020 at 5:30:15 PM UTC-6, Bruce wrote:
>>
>>
>> Consequently, the usual mythology about quantum fluctuations is not true.
>>
>
> *But isn't there factually undeniable, empirical evidence that if one
> repeatedly measures the vacuum energy at some position in space, it
> changes, aka "fluctuates"?  AG*
>


What factually undeniable evidence? How do you measure the vacuum energy at
a point?

Bruce

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Re: The size of the universe



On Saturday, June 13, 2020 at 5:53:27 AM UTC-6, Alan Grayson wrote:
>
>
>
> On Thursday, June 11, 2020 at 7:31:18 PM UTC-6, Bruce wrote:
>>
>> On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:
>>
>>> On 11-06-2020 02:01, Bruce Kellett wrote:
>>>
>>> > Energy and momentum are conserved locally, even in GR where global
>>> > energy conservation fails in a non-static universe.
>>>
>>> Not in the sense you are suggesting. Energy and momentum are constant in 
>>> a closed volume and one can then write down the conservation law in a 
>>> local form. But this so-called "local conservation of energy and 
>>> momentum" does not mean that it's conserved in the sense of having a 
>>> constant value everywhere.
>>>
>>
>>
>> Bullshit. Energy-momentum conservation comes from translational 
>> invariance of the Lagrangian in space and time. Local conservation is 
>> ensured in GR by the vanishing of the covariant derivative of the 
>> Stress-Energy tensor. Local in this sense means on the scale of the galaxy 
>> or more. In the absence of a time-like Killing vector in an expanding 
>> universe, this conservation breaks down on larger scales, such as the scale 
>> of the Hubble expansion.
>>
>> If you have a theory that violates local energy-momentum conservation in 
>> the above sense, then your theory is wrong. Local conservation does not 
>> mean that energy necessarily has the same constant value everywhere.
>>
>> .
>>
>>> >> The expectation value of these energies do fluctuate.
>>> > 
>>> > You can introduce coupled harmonic oscillators, but that is not how
>>> > you form a quantized field theory. Such fluctuations arise from
>>> > non-local couplings -- they are not fluctuations of the original
>>> > quantum field. Energy-momentum is locally conserved, even in GR and an
>>> > expanding universe.
>>> > 
>>>
>>> The Casimir effect, the effective negative pressure of the vacuum is 
>>> another way to see that your arguments based on local energy 
>>> conservation are wrong. Vacuum fluctuations in the local energy density 
>>> do exist and they have measurable effects.
>>>
>>
>>
>> I wondered when this would come up. It is always the last resort of those 
>> who contend that vacuum fluctuations in local energy densities are real. I 
>> remember reading a comprehensive review of the Casimir effect in a 
>> scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did 
>> not keep a reference, and I have been unable to find this paper again. But 
>> I do remember the main points of the analysis: They discuss the 
>> Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of 
>> supposed vacuum fluctuations, but they dismiss this approach as 
>> insufficiently general. They give a detailed account of the Casimir effect 
>> in terms of generalized van der Waals forces. The reason for preferring 
>> this explanation (over vacuum fluctuations, sidestepping the question of 
>> whether these fluctuations exist or not)  is that the van der Waals 
>> explanation extends seamlessly to the Casimir effect between irregular 
>> surfaces -- indeed, to the attractive force between a point and a plane 
>> surface -- where the fluctuation model is silent.
>>
>> Bruce
>>
>
> *I'd like to do a search for this paper. Perhaps you can give me some 
> information, even approximate, in order to find it, such as approximate 
> name, author or authors, approximate date of publication, and anything else 
> you can recall. TIA, AG *
>

*To put it as politely as possible, and undeservedly so, why must ethical 
challenges, yours, be part of this picture? AG *

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Re: The size of the universe



On Saturday, June 13, 2020 at 5:30:15 PM UTC-6, Bruce wrote:
>
> On Sun, Jun 14, 2020 at 3:54 AM smitra > 
> wrote:
>
>> On 13-06-2020 02:57, Bruce Kellett wrote:
>> > 
>> >> My point is that your arguments are
>> >> totally flawed. You stated that a free field theory is analogous to
>> >> a set of independent harmonic oscillators in real space, which is
>> >> nonsense as they are coupled via the (nabla phi)^2 term, it's only in 
>> k-space
>> >> that you have independent oscillators.
>> > 
>> > Momentum space and position space are related by a Fourier transform.
>> > Are you claiming that a Fourier transform violates the conservation
>> > laws?
>>
>> By taking the Fourier transform to decouple the osscilators, you are no 
>> longer considering the local energy. Your argument was that because a 
>> free field theory is basically the same as a collection of 
>> noninteracting SHOs, the fact that energy is conserved means that there 
>> cannot be local fluctuations. But each such independent SHO in k-space 
>> isn't localized in real space. In real space the oscillators are coupled 
>> by the (nabla phi)^2 term and local energy momentum conservation does 
>> invilve a transfer of energy and momentum from one oscillator to 
>> another.
>>
>
> There seems to be something wrong with this. QFT is equivalent to a 
> picture in which there are independent SHOs at every point in space. If 
> these are all in their lowest energy state, then the field is in its lowest 
> energy state. Excitation of one or more of the oscillators corresponds to 
> the presence of more energy (and particles). The higher energy 
> configuration can be analysed in terms of the modes, which are the plane 
> waves of determinate wavelength. If you start with a smooth field with all 
> the oscillators in their ground state, this lowest energy configuration 
> persists until some energy is added from somewhere.
>
> A simple analogy can be given in terms of the surface of a body of water, 
> such as a lake or the sea. If there is a "mirror calm", the surface is 
> completely smooth, and we have the state of lowest energy. This will 
> persist until some energy is added, say from the wind. This can cause 
> ripples which, once formed, will persist in the absence of a driving force 
> until friction dissipates the energy as heat. Adding more energy results in 
> bigger waves, until we can have the massive energy input that is seen in 
> storms.
>
> The lesson I am trying to draw is that ripples on the surface of a lake 
> (waves) cannot arise spontaneously -- they require some energy input, say 
> from the coupling of the wind with the surface of the water. The same is 
> true in inflation. You start off with a uniformly smooth (classical) 
> inflaton field, with the same energy everywhere. Variations in the field, 
> or variations in local energy density, cannot arise spontaneously, they 
> require some energy input from outside. Since quantum fluctuations are 
> assumed to be internal to the field, they cannot add this required energy, 
> so the variations in energy density cannot arise from quantum fluctuations. 
> Quantum fluctuations, insofar as these exist as disconnected Feynman loops, 
> do not have any energy, and do not contribute to any physical effects.
>
> In the Wikipedia article on quantum fluctuations, these fluctuations are 
> said to be a temporary change in the amount of energy at a point in space 
> as explained in the HUP. This is, of course, nonsense, since the 
> uncertainty principle does not suggest any such thing. The time-energy form 
> of the UP:
>
> Delta-t*Delta-E >= hbar/2,
>
> is an inequality. The normal story is that this allows a particle to 
> "borrow" and amount of energy Delta-E from the vacuum provided it pays this 
> amount back in the time allowed by the UP. Unfortunately, the inequality is 
> in the wrong direction for this to make sense. If we "borrow" and amount of 
> energy Delta-E, the the UP says that the uncertainty in time (the time 
> within which the energy must be paid back) is
>
>  Delta-t  >=  hbar/(2*Delta-E).
>
> Which means that Delta-t is unbounded above -- it can take on any 
> arbitrarily large value and still be consistent with the UP. If true, this 
> would mean that energy conservation is impossible (since the vacuum could 
> randomly fluctuate into states of arbitrarily high energy that persisted 
> for arbitrarily long times.) This is contrary to observation, so one of the 
> input assumptions must be wrong. The only relevant input 
> assumption (apart from the UP) is that "borrowing" energy from the vacuum 
> makes sense. Since such an assumption leads to results in manifest 
> contradiction with experience, the assumption must be wrong.
>
> Consequently, the usual mythology about quantum fluctuations is not true.
>

*But isn't there factually undeniable, empirical evidence that if one 
repeatedly measures the vacuum energy at some position in space, it

Re: The size of the universe

2020-06-13 Thread Bruce Kellett

On Sun, Jun 14, 2020 at 3:54 AM smitra  wrote:

> On 13-06-2020 02:57, Bruce Kellett wrote:
> >
> >> My point is that your arguments are
> >> totally flawed. You stated that a free field theory is analogous to
> >> a set of independent harmonic oscillators in real space, which is
> >> nonsense as they are coupled via the (nabla phi)^2 term, it's only in
> k-space
> >> that you have independent oscillators.
> >
> > Momentum space and position space are related by a Fourier transform.
> > Are you claiming that a Fourier transform violates the conservation
> > laws?
>
> By taking the Fourier transform to decouple the osscilators, you are no
> longer considering the local energy. Your argument was that because a
> free field theory is basically the same as a collection of
> noninteracting SHOs, the fact that energy is conserved means that there
> cannot be local fluctuations. But each such independent SHO in k-space
> isn't localized in real space. In real space the oscillators are coupled
> by the (nabla phi)^2 term and local energy momentum conservation does
> invilve a transfer of energy and momentum from one oscillator to
> another.
>

There seems to be something wrong with this. QFT is equivalent to a picture
in which there are independent SHOs at every point in space. If these are
all in their lowest energy state, then the field is in its lowest energy
state. Excitation of one or more of the oscillators corresponds to the
presence of more energy (and particles). The higher energy configuration
can be analysed in terms of the modes, which are the plane waves of
determinate wavelength. If you start with a smooth field with all the
oscillators in their ground state, this lowest energy configuration
persists until some energy is added from somewhere.

A simple analogy can be given in terms of the surface of a body of water,
such as a lake or the sea. If there is a "mirror calm", the surface is
completely smooth, and we have the state of lowest energy. This will
persist until some energy is added, say from the wind. This can cause
ripples which, once formed, will persist in the absence of a driving force
until friction dissipates the energy as heat. Adding more energy results in
bigger waves, until we can have the massive energy input that is seen in
storms.

The lesson I am trying to draw is that ripples on the surface of a lake
(waves) cannot arise spontaneously -- they require some energy input, say
from the coupling of the wind with the surface of the water. The same is
true in inflation. You start off with a uniformly smooth (classical)
inflaton field, with the same energy everywhere. Variations in the field,
or variations in local energy density, cannot arise spontaneously, they
require some energy input from outside. Since quantum fluctuations are
assumed to be internal to the field, they cannot add this required energy,
so the variations in energy density cannot arise from quantum fluctuations.
Quantum fluctuations, insofar as these exist as disconnected Feynman loops,
do not have any energy, and do not contribute to any physical effects.

In the Wikipedia article on quantum fluctuations, these fluctuations are
said to be a temporary change in the amount of energy at a point in space
as explained in the HUP. This is, of course, nonsense, since the
uncertainty principle does not suggest any such thing. The time-energy form
of the UP:

Delta-t*Delta-E >= hbar/2,

is an inequality. The normal story is that this allows a particle to
"borrow" and amount of energy Delta-E from the vacuum provided it pays this
amount back in the time allowed by the UP. Unfortunately, the inequality is
in the wrong direction for this to make sense. If we "borrow" and amount of
energy Delta-E, the the UP says that the uncertainty in time (the time
within which the energy must be paid back) is

 Delta-t  >=  hbar/(2*Delta-E).

Which means that Delta-t is unbounded above -- it can take on any
arbitrarily large value and still be consistent with the UP. If true, this
would mean that energy conservation is impossible (since the vacuum could
randomly fluctuate into states of arbitrarily high energy that persisted
for arbitrarily long times.) This is contrary to observation, so one of the
input assumptions must be wrong. The only relevant input
assumption (apart from the UP) is that "borrowing" energy from the vacuum
makes sense. Since such an assumption leads to results in manifest
contradiction with experience, the assumption must be wrong.

Consequently, the usual mythology about quantum fluctuations is not true.

So quantum fluctuations cannot cause spatial variations in the field.
>
> False, this doesn't follow from the above. Also it the opposite has been
> demonstrated in a massive body of literature on this subject to which
> thousands of experts who are all extremely well versed in QFT have
> contributed to.
>

Can you point me to some recent key papers?

Bruce

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Re: The size of the universe

2020-06-13 Thread smitra


On 13-06-2020 02:57, Bruce Kellett wrote:

On Sat, Jun 13, 2020 at 2:05 AM smitra  wrote:


On 12-06-2020 06:33, Bruce Kellett wrote:

On Fri, Jun 12, 2020 at 2:08 PM smitra  wrote:


Indeed, it doesn't have the same value everywhere. And that makes
the original point you were arguing wrong.


No, all I was arguing twas that the time value at any point does not
change arbitrarily -- it does not fluctuate. There is no requirement
for the value to be the same at every point. But that does not violate
energy conservation -- it just started out that way.


The mere fact that the Casimir force exists proves you wrong. It
doesn't
matter that the naive method to compute this doesn't always work.


Get a grip, Saibal. Are you really claiming that local

energy-momentum

conservation is false?


I never said that it it false.


You implied that energy was not conserved when you related density
fluctuations in the inflaton field to quantum fluctuations.
Fluctuations are variations with time. Spatial variation is distinct.


I never said that.




My point is that your arguments are
totally flawed. You stated that a free field theory is analogous to
a
set of independent harmonic oscillators in real space, which is
nonsense
as they are coupled via the (nabla phi)^2 term, it's only in k-space

that you have independent oscillators.


Momentum space and position space are related by a Fourier transform.
Are you claiming that a Fourier transform violates the conservation
laws?


By taking the Fourier transform to decouple the osscilators, you are no 
longer considering the local energy. Your argument was that because a 
free field theory is basically the same as a collection of 
noninteracting SHOs, the fact that energy is conserved means that there 
cannot be local fluctuations. But each such independent SHO in k-space 
isn't localized in real space. In real space the oscillators are coupled 
by the (nabla phi)^2 term and local energy momentum conservation does 
invilve a transfer of energy and momentum from one oscillator to 
another.





QFT is strictly local. Micro-causality, implemented by the fact that
field commutators vanish for space-like separations, enforces
locality.


True

So quantum fluctuations cannot cause spatial variations in

the field.


False, this doesn't follow from the above. Also it the opposite has been 
demonstrated in a massive body of literature on this subject to which 
thousands of experts who are all extremely well versed in QFT have 
contributed to.





Then you argued that it's really
the time derivative square term that's the most important in case of

inflation, but that's only because of the rapid expansion of the
universe causing the field to become homogeneous and gain an nonzero

expectation value over regions larger than the horizon, which the
allows
one to treat the filed as musical and the fluctuations in there
using
QFT. But you then pretend that all the scientists in that field are
wrong for treating the field classical and only treating the
fluctuations quantum mechanically, which is in principle if the
proper
conditions are met, a rigorous approximation method.


There is no need to misrepresent what I have said. I have no problem
with treating the background as a classical field, and quantizing only
the variations from uniformity. That works, and is not a conceptual
problem. The issue has always been the justification for the gaussian
random field superposed on the classical background in terms of
quantum fluctuations. Variations from a uniform density everywhere
require different changes in energy at different locations. Quantum
effects cannot do this, because quantum effects cannot change the
energy anywhere -- energy and momentum are locally and strictly
conserved in QFT. The random gaussian variations in energy density
must be part of the boundary conditions -- they do not have a quantum
origin.


There is a large amount of literature on this subject which you simply 
ignore. They are mostly given in the references of the articles 
published recently. The fact that you don't see it is not a good 
argument that the entire literature on this subject is wrong.





Now, the Casimir effect,  whether or not you consider it as van der
Waals force or something else, makes it clear that the total energy
content inside an isolated box made of conducting plates in which we
put
a conducting plane, depends on way the plate partitions the volume
of
the box. This follows from the fat that the total energy inside the
box
is conserved and that there exists a Casimir force between
conducting
plates. How you do the calculations, whether or not you attribute
the
force to a van der Waals force etc. doesn't matter here.

The Casimir force in the plate is then different from that of two
infinite plates, but there will in general be some Casimir force.
Moving
the plate all the way until it merges with a boundary plate the box
is
made out of will thus change the total energy contained in

Re: The size of the universe

2020-06-13 Thread Alan Grayson



On Thursday, June 11, 2020 at 7:31:18 PM UTC-6, Bruce wrote:
>
> On Fri, Jun 12, 2020 at 1:53 AM smitra > 
> wrote:
>
>> On 11-06-2020 02:01, Bruce Kellett wrote:
>>
>> > Energy and momentum are conserved locally, even in GR where global
>> > energy conservation fails in a non-static universe.
>>
>> Not in the sense you are suggesting. Energy and momentum are constant in 
>> a closed volume and one can then write down the conservation law in a 
>> local form. But this so-called "local conservation of energy and 
>> momentum" does not mean that it's conserved in the sense of having a 
>> constant value everywhere.
>>
>
>
> Bullshit. Energy-momentum conservation comes from translational invariance 
> of the Lagrangian in space and time. Local conservation is ensured in GR by 
> the vanishing of the covariant derivative of the Stress-Energy tensor. 
> Local in this sense means on the scale of the galaxy or more. In the 
> absence of a time-like Killing vector in an expanding universe, this 
> conservation breaks down on larger scales, such as the scale of the Hubble 
> expansion.
>
> If you have a theory that violates local energy-momentum conservation in 
> the above sense, then your theory is wrong. Local conservation does not 
> mean that energy necessarily has the same constant value everywhere.
>
> .
>
>> >> The expectation value of these energies do fluctuate.
>> > 
>> > You can introduce coupled harmonic oscillators, but that is not how
>> > you form a quantized field theory. Such fluctuations arise from
>> > non-local couplings -- they are not fluctuations of the original
>> > quantum field. Energy-momentum is locally conserved, even in GR and an
>> > expanding universe.
>> > 
>>
>> The Casimir effect, the effective negative pressure of the vacuum is 
>> another way to see that your arguments based on local energy 
>> conservation are wrong. Vacuum fluctuations in the local energy density 
>> do exist and they have measurable effects.
>>
>
>
> I wondered when this would come up. It is always the last resort of those 
> who contend that vacuum fluctuations in local energy densities are real. I 
> remember reading a comprehensive review of the Casimir effect in a 
> scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did 
> not keep a reference, and I have been unable to find this paper again. But 
> I do remember the main points of the analysis: They discuss the 
> Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of 
> supposed vacuum fluctuations, but they dismiss this approach as 
> insufficiently general. They give a detailed account of the Casimir effect 
> in terms of generalized van der Waals forces. The reason for preferring 
> this explanation (over vacuum fluctuations, sidestepping the question of 
> whether these fluctuations exist or not)  is that the van der Waals 
> explanation extends seamlessly to the Casimir effect between irregular 
> surfaces -- indeed, to the attractive force between a point and a plane 
> surface -- where the fluctuation model is silent.
>
> Bruce
>

*I'd like to do a search for this paper. Perhaps you can give me some 
information, even approximate, in order to find it, such as approximate 
name, author or authors, approximate date of publication, and anything else 
you can recall. TIA, AG *

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Re: The size of the universe

2020-06-12 Thread 'Brent Meeker' via Everything List

On 6/12/2020 9:29 PM, Alan Grayson wrote:

On Friday, June 12, 2020 at 10:02:46 PM UTC-6, Brent wrote:

On 6/12/2020 7:08 PM, Bruce Kellett wrote:

On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson
> wrote:

On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:

There is no need to misrepresent what I have said. I have
no problem with treating the background as a classical
field, and quantizing only the variations from
uniformity. That works, and is not a conceptual problem.
The issue has always been the justification for the
gaussian random field superposed on the classical
background in terms of quantum fluctuations. Variations
from a uniform density everywhere require different
changes in energy at different locations. Quantum effects
cannot do this, because quantum effects cannot change the
energy anywhere -- energy and momentum are locally and
strictly conserved in QFT. The random gaussian variations
in energy density must be part of the boundary conditions
-- they do not have a quantum origin.

*I think you're avoiding an important issue here; namely,
it's claimed that the time-energy form of the UP implies
energy fluctuations (and temporary violations of energy
conservation) at a particular region of space, and we know
the UP is implied by the principles of QM. What is the flaw
in this argument? TIA, AG*

That is another old hoary misconception. The time-energy form of
the HUP is an inequality, and it can set a lower limit on
something -- never an upper limit. So if you borrow an energy of
delta-E, it must be repayed in a time GREATER THAN hbar/delta-t,

You mean delta-t > hbar/delta-E.

Brent

*So why can't it be borrowed and paid back any time later? AG
*

That's not what it means. Read Peres.

Brent

Re: The size of the universe



On Friday, June 12, 2020 at 10:02:46 PM UTC-6, Brent wrote:
>
>
>
> On 6/12/2020 7:08 PM, Bruce Kellett wrote:
>
> On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson  > wrote:
>
>> On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote: 
>>>
>>>
>>> There is no need to misrepresent what I have said. I have no problem 
>>> with treating the background as a classical field, and quantizing only the 
>>> variations from uniformity. That works, and is not a conceptual problem. 
>>> The issue has always been the justification for the gaussian random field 
>>> superposed on the classical background in terms of quantum fluctuations. 
>>> Variations from a uniform density everywhere require different changes in 
>>> energy at different locations. Quantum effects cannot do this, because 
>>> quantum effects cannot change the energy anywhere -- energy and momentum 
>>> are locally and strictly conserved in QFT. The random gaussian variations 
>>> in energy density must be part of the boundary conditions -- they do not 
>>> have a quantum origin.
>>>
>>
>> *I think you're avoiding an important issue here; namely, it's claimed 
>> that the time-energy form of the UP implies energy fluctuations (and 
>> temporary violations of energy conservation) at a particular region of 
>> space, and we know the UP is implied by the principles of  QM. What is the 
>> flaw in this argument? TIA, AG*
>>
>
> That is another old hoary misconception. The time-energy form of the HUP 
> is an inequality, and it can set a lower limit on something -- never an 
> upper limit. So if you borrow an energy of delta-E, it must be repayed in a 
> time GREATER THAN hbar/delta-t, 
>
>
> You mean delta-t > hbar/delta-E.
>
> Brent
>

*So why can't it  be borrowed and paid back any time later? AG *

>
> not LESS THAN this time. If it were the case that energy could be 
> 'borrowed' in this way, then energy could never be conserved.
>
> Bruce
> -- 
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>  
> 
> .
>
>
>

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Re: The size of the universe

2020-06-12 Thread 'Brent Meeker' via Everything List

On 6/12/2020 7:08 PM, Bruce Kellett wrote:
On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson > wrote:

On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:

There is no need to misrepresent what I have said. I have no
problem with treating the background as a classical field, and
quantizing only the variations from uniformity. That works,
and is not a conceptual problem. The issue has always been the
justification for the gaussian random field superposed on the
classical background in terms of quantum fluctuations.
Variations from a uniform density everywhere require different
changes in energy at different locations. Quantum effects
cannot do this, because quantum effects cannot change the
energy anywhere -- energy and momentum are locally and
strictly conserved in QFT. The random gaussian variations in
energy density must be part of the boundary conditions -- they
do not have a quantum origin.

*I think you're avoiding an important issue here; namely, it's
claimed that the time-energy form of the UP implies energy
fluctuations (and temporary violations of energy conservation) at
a particular region of space, and we know the UP is implied by the
principles of QM. What is the flaw in this argument? TIA, AG*

That is another old hoary misconception. The time-energy form of the
HUP is an inequality, and it can set a lower limit on something --
never an upper limit. So if you borrow an energy of delta-E, it must
be repayed in a time GREATER THAN hbar/delta-t,

You mean delta-t > hbar/delta-E.

Brent

not LESS THAN this time. If it were the case that energy could be
'borrowed' in this way, then energy could never be conserved.

Bruce
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.

Re: The size of the universe

2020-06-12 Thread 'Brent Meeker' via Everything List




On 6/12/2020 6:50 PM, Alan Grayson wrote:


*I think you're avoiding an important issue here; namely, it's claimed 
that the time-energy form of the UP implies energy fluctuations (and 
temporary violations of energy conservation) at a particular region of 
space, and we know the UP is implied by the principles of QM. What is 
the flaw in this argument? TIA, AG*


No.  The UP is about ideal measurement (preparation) results.

Brent

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Re: The size of the universe



On Friday, June 12, 2020 at 8:18:41 PM UTC-6, Bruce wrote:
>
> On Sat, Jun 13, 2020 at 12:14 PM Alan Grayson  > wrote:
>
>> On Friday, June 12, 2020 at 8:08:28 PM UTC-6, Bruce wrote:
>>>
>>> On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson  
>>> wrote:
>>>
 On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:
>
>
> There is no need to misrepresent what I have said. I have no problem 
> with treating the background as a classical field, and quantizing only 
> the 
> variations from uniformity. That works, and is not a conceptual problem. 
> The issue has always been the justification for the gaussian random field 
> superposed on the classical background in terms of quantum fluctuations. 
> Variations from a uniform density everywhere require different changes in 
> energy at different locations. Quantum effects cannot do this, because 
> quantum effects cannot change the energy anywhere -- energy and momentum 
> are locally and strictly conserved in QFT. The random gaussian variations 
> in energy density must be part of the boundary conditions -- they do not 
> have a quantum origin.
>

 *I think you're avoiding an important issue here; namely, it's claimed 
 that the time-energy form of the UP implies energy fluctuations (and 
 temporary violations of energy conservation) at a particular region of 
 space, and we know the UP is implied by the principles of  QM. What is the 
 flaw in this argument? TIA, AG*

>>>
>>> That is another old hoary misconception. The time-energy form of the HUP 
>>> is an inequality, and it can set a lower limit on something -- never an 
>>> upper limit. So if you borrow an energy of delta-E, it must be repayed in a 
>>> time GREATER THAN hbar/delta-t, not LESS THAN this time. If it were the 
>>> case that energy could be 'borrowed' in this way, then energy could never 
>>> be conserved.
>>>
>>> Bruce
>>>
>>
>> *So why not conclude that energy is never conserved!?*
>>
>
> Because the HUP does not say this!
>

*It does seem to say this; borrow some energy and pay it back any time 
later one wants. AG*
 

> *My problem with this form of the UP is that I have no idea what the 
>> variance of time means in this context.*
>>
>
> The usual explanation is that delta-t in this context is the time taken to 
> do the energy measurement -- the longer the time taken, the more accurate 
> the measurement can be.
>

*Why would the energy measurement be more accurate if one takes more time 
to measure it? AG *

>
> Bruce
>
>> *Brent claims it has something to do with using physical clocks, 
>> according to Peres. But I am skeptical of this explanation. AG *
>>
>

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Re: The size of the universe

2020-06-12 Thread Bruce Kellett

On Sat, Jun 13, 2020 at 12:14 PM Alan Grayson 
wrote:

> On Friday, June 12, 2020 at 8:08:28 PM UTC-6, Bruce wrote:
>>
>> On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson 
>> wrote:
>>
>>> On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:

 There is no need to misrepresent what I have said. I have no problem
 with treating the background as a classical field, and quantizing only the
 variations from uniformity. That works, and is not a conceptual problem.
 The issue has always been the justification for the gaussian random field
 superposed on the classical background in terms of quantum fluctuations.
 Variations from a uniform density everywhere require different changes in
 energy at different locations. Quantum effects cannot do this, because
 quantum effects cannot change the energy anywhere -- energy and momentum
 are locally and strictly conserved in QFT. The random gaussian variations
 in energy density must be part of the boundary conditions -- they do not
 have a quantum origin.

>>>
>>> *I think you're avoiding an important issue here; namely, it's claimed
>>> that the time-energy form of the UP implies energy fluctuations (and
>>> temporary violations of energy conservation) at a particular region of
>>> space, and we know the UP is implied by the principles of  QM. What is the
>>> flaw in this argument? TIA, AG*
>>>
>>
>> That is another old hoary misconception. The time-energy form of the HUP
>> is an inequality, and it can set a lower limit on something -- never an
>> upper limit. So if you borrow an energy of delta-E, it must be repayed in a
>> time GREATER THAN hbar/delta-t, not LESS THAN this time. If it were the
>> case that energy could be 'borrowed' in this way, then energy could never
>> be conserved.
>>
>> Bruce
>>
>
> *So why not conclude that energy is never conserved!?*
>

Because the HUP does not say this!

> *My problem with this form of the UP is that I have no idea what the
> variance of time means in this context.*
>

The usual explanation is that delta-t in this context is the time taken to
do the energy measurement -- the longer the time taken, the more accurate
the measurement can be.

Bruce

> *Brent claims it has something to do with using physical clocks, according
> to Peres. But I am skeptical of this explanation. AG *
>

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Re: The size of the universe



On Friday, June 12, 2020 at 8:08:28 PM UTC-6, Bruce wrote:
>
> On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson  > wrote:
>
>> On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:
>>>
>>>
>>> There is no need to misrepresent what I have said. I have no problem 
>>> with treating the background as a classical field, and quantizing only the 
>>> variations from uniformity. That works, and is not a conceptual problem. 
>>> The issue has always been the justification for the gaussian random field 
>>> superposed on the classical background in terms of quantum fluctuations. 
>>> Variations from a uniform density everywhere require different changes in 
>>> energy at different locations. Quantum effects cannot do this, because 
>>> quantum effects cannot change the energy anywhere -- energy and momentum 
>>> are locally and strictly conserved in QFT. The random gaussian variations 
>>> in energy density must be part of the boundary conditions -- they do not 
>>> have a quantum origin.
>>>
>>
>> *I think you're avoiding an important issue here; namely, it's claimed 
>> that the time-energy form of the UP implies energy fluctuations (and 
>> temporary violations of energy conservation) at a particular region of 
>> space, and we know the UP is implied by the principles of  QM. What is the 
>> flaw in this argument? TIA, AG*
>>
>
> That is another old hoary misconception. The time-energy form of the HUP 
> is an inequality, and it can set a lower limit on something -- never an 
> upper limit. So if you borrow an energy of delta-E, it must be repayed in a 
> time GREATER THAN hbar/delta-t, not LESS THAN this time. If it were the 
> case that energy could be 'borrowed' in this way, then energy could never 
> be conserved.
>
> Bruce
>

*So why not conclude that energy is never conserved!? My problem with this 
form of the UP is that I have no idea what the variance of time means in 
this context. Brent claims it has something to do with using physical 
clocks, according to Peres. But I am skeptical of this explanation. AG *

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Re: The size of the universe

2020-06-12 Thread Bruce Kellett

On Sat, Jun 13, 2020 at 11:50 AM Alan Grayson 
wrote:

> On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:
>>
>>
>> There is no need to misrepresent what I have said. I have no problem with
>> treating the background as a classical field, and quantizing only the
>> variations from uniformity. That works, and is not a conceptual problem.
>> The issue has always been the justification for the gaussian random field
>> superposed on the classical background in terms of quantum fluctuations.
>> Variations from a uniform density everywhere require different changes in
>> energy at different locations. Quantum effects cannot do this, because
>> quantum effects cannot change the energy anywhere -- energy and momentum
>> are locally and strictly conserved in QFT. The random gaussian variations
>> in energy density must be part of the boundary conditions -- they do not
>> have a quantum origin.
>>
>
> *I think you're avoiding an important issue here; namely, it's claimed
> that the time-energy form of the UP implies energy fluctuations (and
> temporary violations of energy conservation) at a particular region of
> space, and we know the UP is implied by the principles of  QM. What is the
> flaw in this argument? TIA, AG*
>

That is another old hoary misconception. The time-energy form of the HUP is
an inequality, and it can set a lower limit on something -- never an upper
limit. So if you borrow an energy of delta-E, it must be repayed in a time
GREATER THAN hbar/delta-t, not LESS THAN this time. If it were the case
that energy could be 'borrowed' in this way, then energy could never be
conserved.

Bruce

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Re: The size of the universe



On Friday, June 12, 2020 at 6:57:29 PM UTC-6, Bruce wrote:
>
> On Sat, Jun 13, 2020 at 2:05 AM smitra > 
> wrote:
>
>> On 12-06-2020 06:33, Bruce Kellett wrote:
>> > On Fri, Jun 12, 2020 at 2:08 PM smitra > 
>> wrote:
>> >> 
>> >> Indeed, it doesn't have the same value everywhere. And that makes
>> >> the original point you were arguing wrong.
>>
>
> No, all I was arguing twas that the time value at any point does not 
> change arbitrarily -- it does not fluctuate. There is no requirement for 
> the value to be the same at every point. But that does not violate energy 
> conservation -- it just started out that way.
>
>
> >> The mere fact that the Casimir force exists proves you wrong. It
>> >> doesn't
>> >> matter that the naive method to compute this doesn't always work.
>> > 
>> > Get a grip, Saibal. Are you really claiming that local energy-momentum
>> > conservation is false?
>>
>> I never said that it it false.
>
>
>
> You implied that energy was not conserved when you related density 
> fluctuations in the inflaton field to quantum fluctuations. Fluctuations 
> are variations with time. Spatial variation is distinct.
>
>
> My point is that your arguments are 
>> totally flawed. You stated that a free field theory is analogous to a 
>> set of independent harmonic oscillators in real space, which is nonsense 
>> as they are coupled via the (nabla phi)^2 term, it's only in k-space 
>> that you have independent oscillators.
>
>
> Momentum space and position space are related by a Fourier transform. Are 
> you claiming that a Fourier transform violates the conservation laws?
>
> QFT is strictly local. Micro-causality, implemented by the fact that field 
> commutators vanish for space-like separations, enforces locality. So 
> quantum fluctuations cannot cause spatial variations in the field.
>
>
> Then you argued that it's really 
>> the time derivative square term that's the most important in case of 
>> inflation, but that's only because of the rapid expansion of the 
>> universe causing the field to become homogeneous and gain an nonzero 
>> expectation value over regions larger than the horizon, which the allows 
>> one to treat the filed as musical and the fluctuations in there using 
>> QFT. But you then pretend that all the scientists in that field are 
>> wrong for treating the field classical and only treating the 
>> fluctuations quantum mechanically, which is in principle if the proper 
>> conditions are met, a rigorous approximation method.
>>
>
> There is no need to misrepresent what I have said. I have no problem with 
> treating the background as a classical field, and quantizing only the 
> variations from uniformity. That works, and is not a conceptual problem. 
> The issue has always been the justification for the gaussian random field 
> superposed on the classical background in terms of quantum fluctuations. 
> Variations from a uniform density everywhere require different changes in 
> energy at different locations. Quantum effects cannot do this, because 
> quantum effects cannot change the energy anywhere -- energy and momentum 
> are locally and strictly conserved in QFT. The random gaussian variations 
> in energy density must be part of the boundary conditions -- they do not 
> have a quantum origin.
>

*I think you're avoiding an important issue here; namely, it's claimed that 
the time-energy form of the UP implies energy fluctuations (and temporary 
violations of energy conservation) at a particular region of space, and we 
know the UP is implied by the principles of  QM. What is the flaw in this 
argument? TIA, AG*

>
> Now, the Casimir effect,  whether or not you consider it as van der 
>> Waals force or something else, makes it clear that the total energy 
>> content inside an isolated box made of conducting plates in which we put 
>> a conducting plane, depends on way the plate partitions the volume of 
>> the box. This follows from the fat that the total energy inside the box 
>> is conserved and that there exists a Casimir force between conducting 
>> plates. How you do the calculations, whether or not you attribute the 
>> force to a van der Waals force etc. doesn't matter here.
>>
>> The Casimir force in the plate is then different from that of two 
>> infinite plates, but there will in general be some Casimir force. Moving 
>> the plate all the way until it merges with a boundary plate the box is 
>> made out of will thus change the total energy contained in the box.
>
>
>
> So what? If you move the plate against the Casimir force you must do work 
> on the plate. This naturally changes the energy -- the box is not a closed 
> system in that case.
>
> Bruce
>
> So, the initial state where the vacuum energy is forced to be localized in 
>> either one part of the volume or the other part has a different energy 
>> content compared to the situation without this restriction. This proves 
>> wring your assertion that you can just consider a free field theory in a 
>>

Re: The size of the universe

2020-06-12 Thread Bruce Kellett

On Sat, Jun 13, 2020 at 2:05 AM smitra  wrote:

> On 12-06-2020 06:33, Bruce Kellett wrote:
> > On Fri, Jun 12, 2020 at 2:08 PM smitra  wrote:
> >>
> >> Indeed, it doesn't have the same value everywhere. And that makes
> >> the original point you were arguing wrong.
>

No, all I was arguing twas that the time value at any point does not change
arbitrarily -- it does not fluctuate. There is no requirement for the value
to be the same at every point. But that does not violate energy
conservation -- it just started out that way.

>> The mere fact that the Casimir force exists proves you wrong. It
> >> doesn't
> >> matter that the naive method to compute this doesn't always work.
> >
> > Get a grip, Saibal. Are you really claiming that local energy-momentum
> > conservation is false?
>
> I never said that it it false.

You implied that energy was not conserved when you related density
fluctuations in the inflaton field to quantum fluctuations. Fluctuations
are variations with time. Spatial variation is distinct.

My point is that your arguments are
> totally flawed. You stated that a free field theory is analogous to a
> set of independent harmonic oscillators in real space, which is nonsense
> as they are coupled via the (nabla phi)^2 term, it's only in k-space
> that you have independent oscillators.

Momentum space and position space are related by a Fourier transform. Are
you claiming that a Fourier transform violates the conservation laws?

QFT is strictly local. Micro-causality, implemented by the fact that field
commutators vanish for space-like separations, enforces locality. So
quantum fluctuations cannot cause spatial variations in the field.

Then you argued that it's really
> the time derivative square term that's the most important in case of
> inflation, but that's only because of the rapid expansion of the
> universe causing the field to become homogeneous and gain an nonzero
> expectation value over regions larger than the horizon, which the allows
> one to treat the filed as musical and the fluctuations in there using
> QFT. But you then pretend that all the scientists in that field are
> wrong for treating the field classical and only treating the
> fluctuations quantum mechanically, which is in principle if the proper
> conditions are met, a rigorous approximation method.
>

There is no need to misrepresent what I have said. I have no problem with
treating the background as a classical field, and quantizing only the
variations from uniformity. That works, and is not a conceptual problem.
The issue has always been the justification for the gaussian random field
superposed on the classical background in terms of quantum fluctuations.
Variations from a uniform density everywhere require different changes in
energy at different locations. Quantum effects cannot do this, because
quantum effects cannot change the energy anywhere -- energy and momentum
are locally and strictly conserved in QFT. The random gaussian variations
in energy density must be part of the boundary conditions -- they do not
have a quantum origin.

Now, the Casimir effect,  whether or not you consider it as van der
> Waals force or something else, makes it clear that the total energy
> content inside an isolated box made of conducting plates in which we put
> a conducting plane, depends on way the plate partitions the volume of
> the box. This follows from the fat that the total energy inside the box
> is conserved and that there exists a Casimir force between conducting
> plates. How you do the calculations, whether or not you attribute the
> force to a van der Waals force etc. doesn't matter here.
>
> The Casimir force in the plate is then different from that of two
> infinite plates, but there will in general be some Casimir force. Moving
> the plate all the way until it merges with a boundary plate the box is
> made out of will thus change the total energy contained in the box.

So what? If you move the plate against the Casimir force you must do work
on the plate. This naturally changes the energy -- the box is not a closed
system in that case.

Bruce

So, the initial state where the vacuum energy is forced to be localized in
> either one part of the volume or the other part has a different energy
> content compared to the situation without this restriction. This proves
> wring your assertion that you can just consider a free field theory in a
> box as a collection of independent SHO in real space. The gradient term
> does matter.
>
> Saibal
>

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Re: The size of the universe

2020-06-12 Thread smitra


On 12-06-2020 06:33, Bruce Kellett wrote:

On Fri, Jun 12, 2020 at 2:08 PM smitra  wrote:


On 12-06-2020 03:31, Bruce Kellett wrote:

On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:


On 11-06-2020 02:01, Bruce Kellett wrote:


Energy and momentum are conserved locally, even in GR where

global

energy conservation fails in a non-static universe.


Not in the sense you are suggesting. Energy and momentum are
constant in
a closed volume and one can then write down the conservation law

in

a
local form. But this so-called "local conservation of energy and
momentum" does not mean that it's conserved in the sense of

having a


constant value everywhere.


Bullshit. Energy-momentum conservation comes from translational
invariance of the Lagrangian in space and time. Local conservation

is

ensured in GR by the vanishing of the covariant derivative of the
Stress-Energy tensor. Local in this sense means on the scale of

the

galaxy or more. In the absence of a time-like Killing vector in an
expanding universe, this conservation breaks down on larger

scales,

such as the scale of the Hubble expansion.

If you have a theory that violates local energy-momentum

conservation

in the above sense, then your theory is wrong. Local conservation

does

not mean that energy necessarily has the same constant value
everywhere.



Indeed, it doesn't have the same value everywhere. And that makes
the
original point you were arguing wrong.


.


The expectation value of these energies do fluctuate.


You can introduce coupled harmonic oscillators, but that is not

how

you form a quantized field theory. Such fluctuations arise from
non-local couplings -- they are not fluctuations of the original
quantum field. Energy-momentum is locally conserved, even in GR

and an

expanding universe.



The Casimir effect, the effective negative pressure of the vacuum

is


another way to see that your arguments based on local energy
conservation are wrong. Vacuum fluctuations in the local energy
density do exist and they have measurable effects.


I wondered when this would come up. It is always the last resort

of

those who contend that vacuum fluctuations in local energy

densities

are real. I remember reading a comprehensive review of the Casimir
effect in a scholarly article in Rev. Mod. Phys. a few years ago.
Unfortunately, I did not keep a reference, and I have been unable

to

find this paper again. But I do remember the main points of the
analysis: They discuss the Mickey-Mouse Comic-Book explanation of

the

Casimir effect in terms of supposed vacuum fluctuations, but they
dismiss this approach as insufficiently general. They give a

detailed

account of the Casimir effect in terms of generalized van der

Waals

forces. The reason for preferring this explanation (over vacuum
fluctuations, sidestepping the question of whether these

fluctuations

exist or not)  is that the van der Waals explanation extends
seamlessly to the Casimir effect between irregular surfaces --

indeed,

to the attractive force between a point and a plane surface --

where

the fluctuation model is silent.

Bruce


The mere fact that the Casimir force exists proves you wrong. It
doesn't
matter that the naive method to compute this doesn't always work.


Get a grip, Saibal. Are you really claiming that local energy-momentum
conservation is false?


I never said that it it false. My point is that your arguments are 
totally flawed. You stated that a free field theory is analogous to a 
set of independent harmonic oscillators in real space, which is nonsense 
as they are coupled via the (nabla phi)^2 term, it's only in k-space 
that you have independent oscillators. Then you argued that it's really 
the time derivative square term that's the most important in case of 
inflation, but that's only because of the rapid expansion of the 
universe causing the field to become homogeneous and gain an nonzero 
expectation value over regions larger than the horizon, which the allows 
one to treat the filed as musical and the fluctuations in there using 
QFT. But you then pretend that all the scientists in that field are 
wrong for treating the field classical and only treating the 
fluctuations quantum mechanically, which is in principle if the proper 
conditions are met, a rigorous approximation method.





About the Casimir effect, in the absence of the paper I mentioned, I
refer you to the Wikipedia article:

 https://en.wikipedia.org/wiki/Casimir_effect

where you will find:
Alternatively, a 2005 paper by Robert Jaffe [1] of MIT states that
"Casimir effects can be formulated and Casimir forces can be computed
without reference to zero-point energies. They are relativistic,
quantum forces between charges and currents. The Casimir force (per
unit area) between parallel plates vanishes as alpha, the fine
structure constant, goes to zero, and the standard result, which
appears to be independent of alpha, corresponds to the alpha
approaching infinity

Re: The size of the universe

2020-06-11 Thread Alan Grayson



On Thursday, June 11, 2020 at 9:57:22 PM UTC-6, Brent wrote:
>
>
>
> On 6/11/2020 8:34 PM, Alan Grayson wrote:
>
> *Alternatively, you might approach this issue by discussing the alleged 
> violation of energy conservation by showing the interpretive flaw in the 
> time-energy form of the UP. Recently, I posed this issue to Brent, several 
> times; precisely, what this means since time isn't a quantum operator. What 
> does the "variance of time" mean in this context? But I never received a 
> reply, from anyone. AG *
>
>
> I thought I did reply to this by pointing to Asher Peres book "Quantum 
> Theory, Concepts and Methods".  It's available free online 
>
>
> https://www.academia.edu/35687651/Peres_-_Quantum_Theory_Concepts_and_Methods.pdf
>
> and has a good chapter discussing the problem of time.  The time-energy UP 
> applies to energy and* time as measured by a physical clock*, not by "t" 
> in the equation.
>
> Brent
>

Actually, I've downloaded it in the past, and will check out your 
reference. However, off the top of my head, I don't see the distinction 
between a physical clock and the "t" in the equation. AG  

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Re: The size of the universe

2020-06-11 Thread Bruce Kellett

On Fri, Jun 12, 2020 at 2:08 PM smitra  wrote:

> On 12-06-2020 03:31, Bruce Kellett wrote:
> > On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:
> >
> >> On 11-06-2020 02:01, Bruce Kellett wrote:
> >>
> >>> Energy and momentum are conserved locally, even in GR where global
> >>> energy conservation fails in a non-static universe.
> >>
> >> Not in the sense you are suggesting. Energy and momentum are
> >> constant in
> >> a closed volume and one can then write down the conservation law in
> >> a
> >> local form. But this so-called "local conservation of energy and
> >> momentum" does not mean that it's conserved in the sense of having a
> >>
> >> constant value everywhere.
> >
> > Bullshit. Energy-momentum conservation comes from translational
> > invariance of the Lagrangian in space and time. Local conservation is
> > ensured in GR by the vanishing of the covariant derivative of the
> > Stress-Energy tensor. Local in this sense means on the scale of the
> > galaxy or more. In the absence of a time-like Killing vector in an
> > expanding universe, this conservation breaks down on larger scales,
> > such as the scale of the Hubble expansion.
> >
> > If you have a theory that violates local energy-momentum conservation
> > in the above sense, then your theory is wrong. Local conservation does
> > not mean that energy necessarily has the same constant value
> > everywhere.
> >
>
> Indeed, it doesn't have the same value everywhere. And that makes the
> original point you were arguing wrong.
>
> > .
> >
>  The expectation value of these energies do fluctuate.
> >>>
> >>> You can introduce coupled harmonic oscillators, but that is not
> >> how
> >>> you form a quantized field theory. Such fluctuations arise from
> >>> non-local couplings -- they are not fluctuations of the original
> >>> quantum field. Energy-momentum is locally conserved, even in GR
> >> and an
> >>> expanding universe.
> >>>
> >>
> >> The Casimir effect, the effective negative pressure of the vacuum is
> >>
> >> another way to see that your arguments based on local energy
> >> conservation are wrong. Vacuum fluctuations in the local energy
> >> density do exist and they have measurable effects.
> >
> > I wondered when this would come up. It is always the last resort of
> > those who contend that vacuum fluctuations in local energy densities
> > are real. I remember reading a comprehensive review of the Casimir
> > effect in a scholarly article in Rev. Mod. Phys. a few years ago.
> > Unfortunately, I did not keep a reference, and I have been unable to
> > find this paper again. But I do remember the main points of the
> > analysis: They discuss the Mickey-Mouse Comic-Book explanation of the
> > Casimir effect in terms of supposed vacuum fluctuations, but they
> > dismiss this approach as insufficiently general. They give a detailed
> > account of the Casimir effect in terms of generalized van der Waals
> > forces. The reason for preferring this explanation (over vacuum
> > fluctuations, sidestepping the question of whether these fluctuations
> > exist or not)  is that the van der Waals explanation extends
> > seamlessly to the Casimir effect between irregular surfaces -- indeed,
> > to the attractive force between a point and a plane surface -- where
> > the fluctuation model is silent.
> >
> > Bruce
>
> The mere fact that the Casimir force exists proves you wrong. It doesn't
> matter that the naive method to compute this doesn't always work.
>

Get a grip, Saibal. Are you really claiming that local energy-momentum
conservation is false?

About the Casimir effect, in the absence of the paper I mentioned, I refer
you to the Wikipedia article:

 https://en.wikipedia.org/wiki/Casimir_effect

where you will find:
Alternatively, a 2005 paper by Robert Jaffe
 of MIT states that "Casimir
effects can be formulated and Casimir forces can be computed without
reference to zero-point energies. They are relativistic, quantum forces
between charges and currents. The Casimir force (per unit area) between
parallel plates vanishes as alpha, the fine structure constant, goes to
zero, and the standard result, which appears to be independent of alpha,
corresponds to the alpha approaching infinity limit," and that "The Casimir
force is simply the (relativistic, retarded
) van der Waals force
between the metal plates."[17]
 Casimir and
Polder's original paper used this method to derive the Casimir-Polder
force. In 1978, Schwinger, DeRadd, and Milton published a similar
derivation for the Casimir Effect between two parallel plates.[18]
 In fact, the
description in terms of van der Waals forces is the only correct
description from the fundamental microscopic perspective,[19]
[20]

Re: The size of the universe

2020-06-11 Thread smitra

On 12-06-2020 03:31, Bruce Kellett wrote:

On Fri, Jun 12, 2020 at 1:53 AM smitra wrote:

On 11-06-2020 02:01, Bruce Kellett wrote:

Energy and momentum are conserved locally, even in GR where global
energy conservation fails in a non-static universe.

Not in the sense you are suggesting. Energy and momentum are
constant in
a closed volume and one can then write down the conservation law in
a
local form. But this so-called "local conservation of energy and
momentum" does not mean that it's conserved in the sense of having a

constant value everywhere.

Bullshit. Energy-momentum conservation comes from translational
invariance of the Lagrangian in space and time. Local conservation is
ensured in GR by the vanishing of the covariant derivative of the
Stress-Energy tensor. Local in this sense means on the scale of the
galaxy or more. In the absence of a time-like Killing vector in an
expanding universe, this conservation breaks down on larger scales,
such as the scale of the Hubble expansion.

If you have a theory that violates local energy-momentum conservation
in the above sense, then your theory is wrong. Local conservation does
not mean that energy necessarily has the same constant value
everywhere.

Indeed, it doesn't have the same value everywhere. And that makes the
original point you were arguing wrong.

The expectation value of these energies do fluctuate.

You can introduce coupled harmonic oscillators, but that is not

how

you form a quantized field theory. Such fluctuations arise from
non-local couplings -- they are not fluctuations of the original
quantum field. Energy-momentum is locally conserved, even in GR

and an

expanding universe.

The Casimir effect, the effective negative pressure of the vacuum is

another way to see that your arguments based on local energy
conservation are wrong. Vacuum fluctuations in the local energy
density
do exist and they have measurable effects.

I wondered when this would come up. It is always the last resort of
those who contend that vacuum fluctuations in local energy densities
are real. I remember reading a comprehensive review of the Casimir
effect in a scholarly article in Rev. Mod. Phys. a few years ago.
Unfortunately, I did not keep a reference, and I have been unable to
find this paper again. But I do remember the main points of the
analysis: They discuss the Mickey-Mouse Comic-Book explanation of the
Casimir effect in terms of supposed vacuum fluctuations, but they
dismiss this approach as insufficiently general. They give a detailed
account of the Casimir effect in terms of generalized van der Waals
forces. The reason for preferring this explanation (over vacuum
fluctuations, sidestepping the question of whether these fluctuations
exist or not) is that the van der Waals explanation extends
seamlessly to the Casimir effect between irregular surfaces -- indeed,
to the attractive force between a point and a plane surface -- where
the fluctuation model is silent.

Bruce

The mere fact that the Casimir force exists proves you wrong. It doesn't
matter that the naive method to compute this doesn't always work.

Saibal

Re: The size of the universe

2020-06-11 Thread 'Brent Meeker' via Everything List




On 6/11/2020 8:34 PM, Alan Grayson wrote:
*Alternatively, you might approach this issue by discussing the 
alleged violation of energy conservation by showing the interpretive 
flaw in the time-energy form of the UP. Recently, I posed this issue 
to Brent, several times; precisely, what this means since time isn't a 
quantum operator. What does the "variance of time" mean in this 
context? But I never received a reply, from anyone. AG *


I thought I did reply to this by pointing to Asher Peres book "Quantum 
Theory, Concepts and Methods".  It's available free online


https://www.academia.edu/35687651/Peres_-_Quantum_Theory_Concepts_and_Methods.pdf

and has a good chapter discussing the problem of time.  The time-energy 
UP applies to energy and/time as measured by a physical clock/, not by 
"t" in the equation.


Brent

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Re: The size of the universe

2020-06-11 Thread Alan Grayson



On Thursday, June 11, 2020 at 9:16:18 PM UTC-6, Alan Grayson wrote:
>
>
>
> On Thursday, June 11, 2020 at 7:31:18 PM UTC-6, Bruce wrote:
>>
>> On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:
>>
>>> On 11-06-2020 02:01, Bruce Kellett wrote:
>>>
>>> > Energy and momentum are conserved locally, even in GR where global
>>> > energy conservation fails in a non-static universe.
>>>
>>> Not in the sense you are suggesting. Energy and momentum are constant in 
>>> a closed volume and one can then write down the conservation law in a 
>>> local form. But this so-called "local conservation of energy and 
>>> momentum" does not mean that it's conserved in the sense of having a 
>>> constant value everywhere.
>>>
>>
>>
>> Bullshit. Energy-momentum conservation comes from translational 
>> invariance of the Lagrangian in space and time. Local conservation is 
>> ensured in GR by the vanishing of the covariant derivative of the 
>> Stress-Energy tensor. Local in this sense means on the scale of the galaxy 
>> or more. In the absence of a time-like Killing vector in an expanding 
>> universe, this conservation breaks down on larger scales, such as the scale 
>> of the Hubble expansion.
>>
>> If you have a theory that violates local energy-momentum conservation in 
>> the above sense, then your theory is wrong. Local conservation does not 
>> mean that energy necessarily has the same constant value everywhere.
>>
>> .
>>
>>> >> The expectation value of these energies do fluctuate.
>>> > 
>>> > You can introduce coupled harmonic oscillators, but that is not how
>>> > you form a quantized field theory. Such fluctuations arise from
>>> > non-local couplings -- they are not fluctuations of the original
>>> > quantum field. Energy-momentum is locally conserved, even in GR and an
>>> > expanding universe.
>>> > 
>>>
>>> The Casimir effect, the effective negative pressure of the vacuum is 
>>> another way to see that your arguments based on local energy 
>>> conservation are wrong. Vacuum fluctuations in the local energy density 
>>> do exist and they have measurable effects.
>>>
>>
>>
>> I wondered when this would come up. It is always the last resort of those 
>> who contend that vacuum fluctuations in local energy densities are real. I 
>> remember reading a comprehensive review of the Casimir effect in a 
>> scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did 
>> not keep a reference, and I have been unable to find this paper again. 
>>
>
> *If it's in this scholarly journal, I would think it's accessible and 
> could put the Casimir explanation where it belongs; in the trash heap of 
> history. AG*
>

*Alternatively, you might approach this issue by discussing the alleged 
violation of energy conservation by showing the interpretive flaw in the 
time-energy form of the UP. Recently, I posed this issue to Brent, several 
times; precisely, what this means since time isn't a quantum operator. What 
does the "variance of time" mean in this context? But I never received a 
reply, from anyone. AG *

 

>
>  
>
>> But I do remember the main points of the analysis: They discuss the 
>> Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of 
>> supposed vacuum fluctuations, but they dismiss this approach as 
>> insufficiently general. They give a detailed account of the Casimir effect 
>> in terms of generalized van der Waals forces. The reason for preferring 
>> this explanation (over vacuum fluctuations, sidestepping the question of 
>> whether these fluctuations exist or not)  is that the van der Waals 
>> explanation extends seamlessly to the Casimir effect between irregular 
>> surfaces -- indeed, to the attractive force between a point and a plane 
>> surface -- where the fluctuation model is silent.
>>
>> Bruce
>>
>

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Re: The size of the universe

2020-06-11 Thread Alan Grayson



On Thursday, June 11, 2020 at 7:31:18 PM UTC-6, Bruce wrote:
>
> On Fri, Jun 12, 2020 at 1:53 AM smitra > 
> wrote:
>
>> On 11-06-2020 02:01, Bruce Kellett wrote:
>>
>> > Energy and momentum are conserved locally, even in GR where global
>> > energy conservation fails in a non-static universe.
>>
>> Not in the sense you are suggesting. Energy and momentum are constant in 
>> a closed volume and one can then write down the conservation law in a 
>> local form. But this so-called "local conservation of energy and 
>> momentum" does not mean that it's conserved in the sense of having a 
>> constant value everywhere.
>>
>
>
> Bullshit. Energy-momentum conservation comes from translational invariance 
> of the Lagrangian in space and time. Local conservation is ensured in GR by 
> the vanishing of the covariant derivative of the Stress-Energy tensor. 
> Local in this sense means on the scale of the galaxy or more. In the 
> absence of a time-like Killing vector in an expanding universe, this 
> conservation breaks down on larger scales, such as the scale of the Hubble 
> expansion.
>
> If you have a theory that violates local energy-momentum conservation in 
> the above sense, then your theory is wrong. Local conservation does not 
> mean that energy necessarily has the same constant value everywhere.
>
> .
>
>> >> The expectation value of these energies do fluctuate.
>> > 
>> > You can introduce coupled harmonic oscillators, but that is not how
>> > you form a quantized field theory. Such fluctuations arise from
>> > non-local couplings -- they are not fluctuations of the original
>> > quantum field. Energy-momentum is locally conserved, even in GR and an
>> > expanding universe.
>> > 
>>
>> The Casimir effect, the effective negative pressure of the vacuum is 
>> another way to see that your arguments based on local energy 
>> conservation are wrong. Vacuum fluctuations in the local energy density 
>> do exist and they have measurable effects.
>>
>
>
> I wondered when this would come up. It is always the last resort of those 
> who contend that vacuum fluctuations in local energy densities are real. I 
> remember reading a comprehensive review of the Casimir effect in a 
> scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did 
> not keep a reference, and I have been unable to find this paper again. 
>

*If it's in this scholarly journal, I would think it's accessible and could 
put the Casimir explanation where it belongs; in the trash heap of history. 
AG*

 

> But I do remember the main points of the analysis: They discuss the 
> Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of 
> supposed vacuum fluctuations, but they dismiss this approach as 
> insufficiently general. They give a detailed account of the Casimir effect 
> in terms of generalized van der Waals forces. The reason for preferring 
> this explanation (over vacuum fluctuations, sidestepping the question of 
> whether these fluctuations exist or not)  is that the van der Waals 
> explanation extends seamlessly to the Casimir effect between irregular 
> surfaces -- indeed, to the attractive force between a point and a plane 
> surface -- where the fluctuation model is silent.
>
> Bruce
>

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Re: The size of the universe

2020-06-11 Thread Bruce Kellett

On Fri, Jun 12, 2020 at 1:53 AM smitra  wrote:

> On 11-06-2020 02:01, Bruce Kellett wrote:
>
> > Energy and momentum are conserved locally, even in GR where global
> > energy conservation fails in a non-static universe.
>
> Not in the sense you are suggesting. Energy and momentum are constant in
> a closed volume and one can then write down the conservation law in a
> local form. But this so-called "local conservation of energy and
> momentum" does not mean that it's conserved in the sense of having a
> constant value everywhere.
>

Bullshit. Energy-momentum conservation comes from translational invariance
of the Lagrangian in space and time. Local conservation is ensured in GR by
the vanishing of the covariant derivative of the Stress-Energy tensor.
Local in this sense means on the scale of the galaxy or more. In the
absence of a time-like Killing vector in an expanding universe, this
conservation breaks down on larger scales, such as the scale of the Hubble
expansion.

If you have a theory that violates local energy-momentum conservation in
the above sense, then your theory is wrong. Local conservation does not
mean that energy necessarily has the same constant value everywhere.

.

> >> The expectation value of these energies do fluctuate.
> >
> > You can introduce coupled harmonic oscillators, but that is not how
> > you form a quantized field theory. Such fluctuations arise from
> > non-local couplings -- they are not fluctuations of the original
> > quantum field. Energy-momentum is locally conserved, even in GR and an
> > expanding universe.
> >
>
> The Casimir effect, the effective negative pressure of the vacuum is
> another way to see that your arguments based on local energy
> conservation are wrong. Vacuum fluctuations in the local energy density
> do exist and they have measurable effects.
>

I wondered when this would come up. It is always the last resort of those
who contend that vacuum fluctuations in local energy densities are real. I
remember reading a comprehensive review of the Casimir effect in a
scholarly article in Rev. Mod. Phys. a few years ago. Unfortunately, I did
not keep a reference, and I have been unable to find this paper again. But
I do remember the main points of the analysis: They discuss the
Mickey-Mouse Comic-Book explanation of the Casimir effect in terms of
supposed vacuum fluctuations, but they dismiss this approach as
insufficiently general. They give a detailed account of the Casimir effect
in terms of generalized van der Waals forces. The reason for preferring
this explanation (over vacuum fluctuations, sidestepping the question of
whether these fluctuations exist or not)  is that the van der Waals
explanation extends seamlessly to the Casimir effect between irregular
surfaces -- indeed, to the attractive force between a point and a plane
surface -- where the fluctuation model is silent.

Bruce

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Re: The size of the universe

2020-06-11 Thread smitra


On 11-06-2020 02:01, Bruce Kellett wrote:

On Wed, Jun 10, 2020 at 11:48 PM smitra  wrote:


On 09-06-2020 01:32, Bruce Kellett wrote:

On Mon, Jun 8, 2020 at 10:33 PM smitra  wrote:


You are confusing the nontechnical introduction for the rigorous
content that comes later.


Where later? The only justification offered for the addition of a
random "fluctuation" field to the classical background inflaton

field

is the hand-waving heuristics of the introduction. Sure, he is
reasonably rigorous in his quantization of this added

"fluctuation"

field, but that does not justify it in the first place.


It is mentioned that the field can be treated in a classical way
with
refs to the literature. You then only need a quantum description for
the
fluctuations, so the classical field is treated as effective
background
field.


I am aware of this. This was, in fact, the problem that I pointed to.
This addition of "fluctuations", even if they are quantized
rigorously, is still unjustified and ad hoc.



They do proceed in a heuristic way, but this is not unjustified.
Your arguments against it based on energy conservation are not

valid.


Oh! Where do my arguments based on energy conservation fail?


Your arguments fail because you are considering the total energy of
the
entire universe. If you consider the energy of a field in a box and
impose boundaryy conditions then you have closed system and you can
consider the system to be in an eigenstate of the Hamiltonian where
the
total energy and the square of the energy are well defined and the
expectation value of the latter is then equal to the square of the
former, so no fluctuations.

But the problem at hand is to consider the local energy density at
some
position. This is not conserved!


Energy and momentum are conserved locally, even in GR where global
energy conservation fails in a non-static universe.


Not in the sense you are suggesting. Energy and momentum are constant in 
a closed volume and one can then write down the conservation law in a 
local form. But this so-called "local conservation of energy and 
momentum" does not mean that it's conserved in the sense of having a 
constant value everywhere.



And if
it were as simple as that then no one in that field who are all

big

experts in QFT would write articles saying that quantum

fluctuations

are a source of the density fluctuations.


That is just an argument from authority -- which justifies

nothing.

After all, there was a time when all the authorities thought that

the

stars were attached to a crystalline "celestial sphere", and that

the

earth was the centre of the universe (and flat!).


What I'm saying is not that we just need to blindly trust the
experts,
but rather that it's not plausible that with their level of
expertise
they could have overlooked a counterargument based on elementary
quantum
mechanics.


What we need is a coherent argument. As pointed out, experts are
frequently wrong, and science is not decided by consensus.


That doesn't mean that it's plausible that they are could be wrong about 
a the very elementary issues you are raising here.





The energy density of a field does
have a variance just like the field strength itself has, and this
then does couple to gravity.


In quantum mechanics, all that can have variances are

superpositions

of eigenstates. Conservation laws forbid variations of energy (or
other conserved quantities) in eigenstates. The vacuum is, by
definition, an energy eigenstate (the lowest possible energy

state),

so its energy cannot fluctuate, and does not have a variance.
Similarly for a simple harmonic oscillator, and the SHO is a model

for

the modes (energy eigenstates) that make up a general quantum

field.


The vacuum energy from zero point energies of quantum fields does

not

couple to gravity -- that is the 120 orders of magnitude mistake

about

the origin of the cosmological constant. The non-connected vacuum
loops of perturbation theory are all of strictly zero energy, and

they

do not couple to gravity. If they did, they would no longer be
non-connected, and would merely form standard radiative

corrections to

propagators or vertex functions.



You only have decoupled SHO in momentum space, assuming that there
are
no couplings to other fields or a phi^4 self-interaction.


Do you not know what 'decoupled' means? It means that although fields
may self-interact (through phi^4 terms, for instance), and may
interact with the other fields in the theory, there are no external
legs, or couplings to external systems. Such decoupled closed loops in
QFT do not contribute to the physics, and they are strictly of zero
energy.


In real space
the SHO are coupled via the 1/2 (nabla psi)^2 term.


I think that in inflation theory, gradient terms in the fields are
generally neglected as irrelevant compared to the time variation.
Besides, such non-local effects are irrelevant for local energy
conservation.


So, the local energy
in a small

Re: The size of the universe

2020-06-10 Thread Bruce Kellett

On Wed, Jun 10, 2020 at 11:48 PM smitra  wrote:

> On 09-06-2020 01:32, Bruce Kellett wrote:
> > On Mon, Jun 8, 2020 at 10:33 PM smitra  wrote:
> >>
> >> You are confusing the nontechnical introduction for the rigorous
> >> content that comes later.
> >
> > Where later? The only justification offered for the addition of a
> > random "fluctuation" field to the classical background inflaton field
> > is the hand-waving heuristics of the introduction. Sure, he is
> > reasonably rigorous in his quantization of this added "fluctuation"
> > field, but that does not justify it in the first place.
>
> It is mentioned that the field can be treated in a classical way with
> refs to the literature. You then only need a quantum description for the
> fluctuations, so the classical field is treated as effective background
> field.
>


I am aware of this. This was, in fact, the problem that I pointed to. This
addition of "fluctuations", even if they are quantized rigorously, is still
unjustified and ad hoc.

>>
> >> They do proceed in a heuristic way, but this is not unjustified.
> >> Your arguments against it based on energy conservation are not valid.
> >
> > Oh! Where do my arguments based on energy conservation fail?
>
> Your arguments fail because you are considering the total energy of the
> entire universe. If you consider the energy of a field in a box and
> impose boundaryy conditions then you have closed system and you can
> consider the system to be in an eigenstate of the Hamiltonian where the
> total energy and the square of the energy are well defined and the
> expectation value of the latter is then equal to the square of the
> former, so no fluctuations.
>
> But the problem at hand is to consider the local energy density at some
> position. This is not conserved!
>


Energy and momentum are conserved locally, even in GR where global energy
conservation fails in a non-static universe.



> >> And if
> >> it were as simple as that then no one in that field who are all big
> >> experts in QFT would write articles saying that quantum fluctuations
> >> are a source of the density fluctuations.
> >
> > That is just an argument from authority -- which justifies nothing.
> > After all, there was a time when all the authorities thought that the
> > stars were attached to a crystalline "celestial sphere", and that the
> > earth was the centre of the universe (and flat!).
>
> What I'm saying is not that we just need to blindly trust the experts,
> but rather that it's not plausible that with their level of expertise
> they could have overlooked a counterargument based on elementary quantum
> mechanics.
>

What we need is a coherent argument. As pointed out, experts are frequently
wrong, and science is not decided by consensus.


>> The energy density of a field does
> >> have a variance just like the field strength itself has, and this
> >> then does couple to gravity.
> >
> > In quantum mechanics, all that can have variances are superpositions
> > of eigenstates. Conservation laws forbid variations of energy (or
> > other conserved quantities) in eigenstates. The vacuum is, by
> > definition, an energy eigenstate (the lowest possible energy state),
> > so its energy cannot fluctuate, and does not have a variance.
> > Similarly for a simple harmonic oscillator, and the SHO is a model for
> > the modes (energy eigenstates) that make up a general quantum field.
> >
> > The vacuum energy from zero point energies of quantum fields does not
> > couple to gravity -- that is the 120 orders of magnitude mistake about
> > the origin of the cosmological constant. The non-connected vacuum
> > loops of perturbation theory are all of strictly zero energy, and they
> > do not couple to gravity. If they did, they would no longer be
> > non-connected, and would merely form standard radiative corrections to
> > propagators or vertex functions.
> >
>
> You only have decoupled SHO in momentum space, assuming that there are
> no couplings to other fields or a phi^4 self-interaction.



Do you not know what 'decoupled' means? It means that although fields may
self-interact (through phi^4 terms, for instance), and may interact with
the other fields in the theory, there are no external legs, or couplings to
external systems. Such decoupled closed loops in QFT do not contribute to
the physics, and they are strictly of zero energy.

In real space
> the SHO are coupled via the 1/2 (nabla psi)^2 term.



I think that in inflation theory, gradient terms in the fields are
generally neglected as irrelevant compared to the time variation. Besides,
such non-local effects are irrelevant for local energy conservation.


So, the local energy
> in a small volume is not contained in a set of SHO that are decoupled
> from the other oscillators. The coupling is trivial in the sense that
> one can decouple the oscillators by performing a Fourier-transform, but
> you are then working with linear combinations of the SHO in real space.
>


Maybe that is

Re: The size of the universe

2020-06-10 Thread smitra


On 09-06-2020 01:32, Bruce Kellett wrote:

On Mon, Jun 8, 2020 at 10:33 PM smitra  wrote:


On 08-06-2020 13:01, Bruce Kellett wrote:

On Mon, Jun 8, 2020 at 7:09 PM smitra  wrote:


On 07-06-2020 01:16, Bruce Kellett wrote:


Applying the idea of quantum fluctuations to the inflaton field

is

a mistake, since inflation is based on a classical field. And you

do

not quantize a classical field by adding "quantum fluctuations".

It's an approximate way to do computations that can be justified
rigorously, see e.g. these lecture notes:

https://www.nikhef.nl/~mpostma/inflation.pdf

section 3 on page 15 and further.


If that is your idea of a rigorous justification.my

mind

boggles.
It seems to rely on the old failed heuristic of "vacuum

fluctuations"

as particle-antiparicle pairs: "The quantum vacuum is never empty,
particle and anti-particle pairs constantly pop out of the vacuum

and

annihilate again. During inflation, due to the enormous expansion,

the

particle and antiparticle are ripped apart, and they may get

separated

by a distance larger than the causal horizon H−1, and cannot

find

each other again to annihilate. They remain as perturbations on

the

background."

This is nonsense, since there are no such particle-antiprticle

pairs

continuously formed in the vacuum state -- the vacuum does not
fluctuate.


You are confusing the nontechnical introduction for the rigorous
content
that comes later.


Where later? The only justification offered for the addition of a
random "fluctuation" field to the classical background inflaton field
is the hand-waving heuristics of the introduction. Sure, he is
reasonably rigorous in his quantization of this added "fluctuation"
field, but that does not justify it in the first place.


It is mentioned that the field can be treated in a classical way with 
refs to the literature. You then only need a quantum description for the 
fluctuations, so the classical field is treated as effective background 
field.



It is this phenomena what Jason referred to. In the
scientific papers on inflation they may go about computing the
effects
of the fluctuations in a semi-classical way by putting in the
fluctuations by hand in classical equations of motion, but

there

is a solid theoretical basis for such an approach.


No, there is not. It is entirely ad hoc. The problem stems from
the fact that the scalar inflaton field has the dimensions of

energy,

so, because energy is strictly conserved, the field value cannot
fluctuate.



It's not ad hoc, it's all explained here:

https://www.nikhef.nl/~mpostma/inflation.pdf


That article is a reasonably comprehensive account of the standard
notions of inflation -- but it still relies on failed heuristics

and

ad hoc notions. Nothing rigourous here.

Closed virtual particle loops in the vacuum are a well-known
phenomenon in perturbation approaches to QFT, but because of

energy

conservation, these loops are strictly of zero energy-momentum.

Since

they are not coupled to anything, so they do not affect any

measurable

physics. At most they add an overall undetectable phase to the

wave

function.



They do proceed in a heuristic way, but this is not unjustified.
Your
arguments against it based on energy conservation are not valid.


Oh! Where do my arguments based on energy conservation fail?


Your arguments fail because you are considering the total energy of the 
entire universe. If you consider the energy of a field in a box and 
impose boundaryy conditions then you have closed system and you can 
consider the system to be in an eigenstate of the Hamiltonian where the 
total energy and the square of the energy are well defined and the 
expectation value of the latter is then equal to the square of the 
former, so no fluctuations.


But the problem at hand is to consider the local energy density at some 
position. This is not conserved!





And if
it were as simple as that then no one in that field who are all big
experts in QFT would write articles saying that quantum fluctuations
are
a source of the density fluctuations.


That is just an argument from authority -- which justifies nothing.
After all, there was a time when all the authorities thought that the
stars were attached to a crystalline "celestial sphere", and that the
earth was the centre of the universe (and flat!).


What I'm saying is not that we just need to blindly trust the experts, 
but rather that it's not plausible that with their level of expertise 
they could have overlooked a counterargument based on elementary quantum 
mechanics.






The energy density of a field does
have a variance just like the field strength itself has, and this
then
does couple to gravity.


In quantum mechanics, all that can have variances are superpositions
of eigenstates. Conservation laws forbid variations of energy (or
other conserved quantities) in eigenstates. The vacuum is, by
definition, an energy eigenstate (the lowest possible energy state),
so

Re: The size of the universe

2020-06-08 Thread Bruce Kellett

On Mon, Jun 8, 2020 at 10:33 PM smitra  wrote:

> On 08-06-2020 13:01, Bruce Kellett wrote:
> > On Mon, Jun 8, 2020 at 7:09 PM smitra  wrote:
> >
> >> On 07-06-2020 01:16, Bruce Kellett wrote:
> >>
> >>> Applying the idea of quantum fluctuations to the inflaton field is
> >> a mistake, since inflation is based on a classical field. And you do
> >> not quantize a classical field by adding "quantum fluctuations".
> >>
> >> It's an approximate way to do computations that can be justified
> >> rigorously, see e.g. these lecture notes:
> >>
> >> https://www.nikhef.nl/~mpostma/inflation.pdf
> >>
> >> section 3 on page 15 and further.
> >
> > If that is your idea of a rigorous justification.my mind
> > boggles.
> > It seems to rely on the old failed heuristic of "vacuum fluctuations"
> > as particle-antiparicle pairs: "The quantum vacuum is never empty,
> > particle and anti-particle pairs constantly pop out of the vacuum and
> > annihilate again. During inflation, due to the enormous expansion, the
> > particle and antiparticle are ripped apart, and they may get separated
> > by a distance larger than the causal horizon H−1, and cannot find
> > each other again to annihilate. They remain as perturbations on the
> > background."
> >
> > This is nonsense, since there are no such particle-antiprticle pairs
> > continuously formed in the vacuum state -- the vacuum does not
> > fluctuate.
>
> You are confusing the nontechnical introduction for the rigorous content
> that comes later.
>

Where later? The only justification offered for the addition of a random
"fluctuation" field to the classical background inflaton field is the
hand-waving heuristics of the introduction. Sure, he is reasonably rigorous
in his quantization of this added "fluctuation" field, but that does not
justify it in the first place.

 It is this phenomena what Jason referred to. In the
>  scientific papers on inflation they may go about computing the
>  effects
>  of the fluctuations in a semi-classical way by putting in the
>  fluctuations by hand in classical equations of motion, but there
>  is a solid theoretical basis for such an approach.
> >>>
> >>> No, there is not. It is entirely ad hoc. The problem stems from
> >>> the fact that the scalar inflaton field has the dimensions of energy,
> >>> so, because energy is strictly conserved, the field value cannot
> >>> fluctuate.
> >>>
> >>
> >> It's not ad hoc, it's all explained here:
> >>
> >> https://www.nikhef.nl/~mpostma/inflation.pdf
> >
> > That article is a reasonably comprehensive account of the standard
> > notions of inflation -- but it still relies on failed heuristics and
> > ad hoc notions. Nothing rigourous here.
> >
> > Closed virtual particle loops in the vacuum are a well-known
> > phenomenon in perturbation approaches to QFT, but because of energy
> > conservation, these loops are strictly of zero energy-momentum. Since
> > they are not coupled to anything, so they do not affect any measurable
> > physics. At most they add an overall undetectable phase to the wave
> > function.
> >
>
> They do proceed in a heuristic way, but this is not unjustified. Your
> arguments against it based on energy conservation are not valid.

Oh! Where do my arguments based on energy conservation fail?

And if
> it were as simple as that then no one in that field who are all big
> experts in QFT would write articles saying that quantum fluctuations are
> a source of the density fluctuations.

That is just an argument from authority -- which justifies nothing. After
all, there was a time when all the authorities thought that the stars were
attached to a crystalline "celestial sphere", and that the earth was the
centre of the universe (and flat!).

The energy density of a field does
> have a variance just like the field strength itself has, and this then
> does couple to gravity.
>

In quantum mechanics, all that can have variances are superpositions of
eigenstates. Conservation laws forbid variations of energy (or other
conserved quantities) in eigenstates. The vacuum is, by definition, an
energy eigenstate (the lowest possible energy state), so its energy cannot
fluctuate, and does not have a variance. Similarly for a simple harmonic
oscillator, and the SHO is a model for the modes (energy eigenstates) that
make up a general quantum field.

The vacuum energy from zero point energies of quantum fields does not
couple to gravity -- that is the 120 orders of magnitude mistake about the
origin of the cosmological constant. The non-connected vacuum loops of
perturbation theory are all of strictly zero energy, and they do not
cou[ple to gravity. If they did, they would no longer be non-connected, and
would merely form standard radiative corrections to propagators or vertex
functions.

Bruce

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Re: The size of the universe

2020-06-08 Thread smitra

On 08-06-2020 13:01, Bruce Kellett wrote:

On Mon, Jun 8, 2020 at 7:09 PM smitra wrote:

On 07-06-2020 01:16, Bruce Kellett wrote:

Applying the idea of quantum fluctuations to the inflaton field is

mistake, since inflation is based on a classical field. And you do

not

quantize a classical field by adding "quantum fluctuations".

It's an approximate way to do computations that can be justified
rigorously, see e.g. these lecture notes:

https://www.nikhef.nl/~mpostma/inflation.pdf

section 3 on page 15 and further.

If that is your idea of a rigorous justification.my mind
boggles.
It seems to rely on the old failed heuristic of "vacuum fluctuations"
as particle-antiparicle pairs: "The quantum vacuum is never empty,
particle and anti-particle pairs constantly pop out of the vacuum and
annihilate again. During inflation, due to the enormous expansion, the
particle and antiparticle are ripped apart, and they may get separated
by a distance larger than the causal horizon H−1, and cannot find
each other again to annihilate. They remain as perturbations on the
background."

This is nonsense, since there are no such particle-antiprticle pairs
continuously formed in the vacuum state -- the vacuum does not
fluctuate.

You are confusing the nontechnical introduction for the rigorous content
that comes later.

It is this phenomena what Jason referred to. In the
scientific papers on inflation they may go about computing the
effects
of the fluctuations in a semi-classical way by putting in the
fluctuations by hand in classical equations of motion, but there

a solid theoretical basis for such an approach.

No, there is not. It is entirely ad hoc. The problem stems from

the

fact that the scalar inflaton field has the dimensions of energy,

so,

because energy is strictly conserved, the field value cannot
fluctuate.

It's not ad hoc, it's all explained here:

https://www.nikhef.nl/~mpostma/inflation.pdf

That article is a reasonably comprehensive account of the standard
notions of inflation -- but it still relies on failed heuristics and
ad hoc notions. Nothing rigourous here.

Closed virtual particle loops in the vacuum are a well-known
phenomenon in perturbation approaches to QFT, but because of energy
conservation, these loops are strictly of zero energy-momentum. Since
they are not coupled to anything, so they do not affect any measurable
physics. At most they add an overall undetectable phase to the wave
function.

They do proceed in a heuristic way, but this is not unjustified. Your
arguments against it based on energy conservation are not valid. And if
it were as simple as that then no one in that field who are all big
experts in QFT would write articles saying that quantum fluctuations are
a source of the density fluctuations. The energy density of a field does
have a variance just like the field strength itself has, and this then
does couple to gravity.

Saibal

Re: The size of the universe

2020-06-08 Thread Bruce Kellett

On Mon, Jun 8, 2020 at 7:09 PM smitra  wrote:

> On 07-06-2020 01:16, Bruce Kellett wrote:
>
> > Applying the idea of quantum fluctuations to the inflaton field is a
> > mistake, since inflation is based on a classical field. And you do not
> > quantize a classical field by adding "quantum fluctuations".
>
> It's an approximate way to do computations that can be justified
> rigorously, see e.g. these lecture notes:
>
> https://www.nikhef.nl/~mpostma/inflation.pdf
>
> section 3 on page 15 and further.
>

If that is your idea of a rigorous justification.my mind
boggles.
It seems to rely on the old failed heuristic of "vacuum fluctuations" as
particle-antiparicle pairs: "The quantum vacuum is never empty, particle
and anti-particle pairs constantly pop out of the vacuum and annihilate
again. During inflation, due to the enormous expansion, the particle and
antiparticle are ripped apart, and they may get separated by a distance
larger than the causal horizon H−1, and cannot find each other again to
annihilate. They remain as perturbations on the background."

This is nonsense, since there are no such particle-antiprticle pairs
continuously formed in the vacuum state -- the vacuum does not fluctuate.

>
> >> It is this phenomena what Jason referred to. In the
> >> scientific papers on inflation they may go about computing the
> >> effects
> >> of the fluctuations in a semi-classical way by putting in the
> >> fluctuations by hand in classical equations of motion, but there is
> >> a solid theoretical basis for such an approach.
> >
> > No, there is not. It is entirely ad hoc. The problem stems from the
> > fact that the scalar inflaton field has the dimensions of energy, so,
> > because energy is strictly conserved, the field value cannot
> > fluctuate.
> >
>
> It's not ad hoc, it's all explained here:
>
> https://www.nikhef.nl/~mpostma/inflation.pdf
>

That article is a reasonably comprehensive account of the standard notions
of inflation -- but it still relies on failed heuristics and ad hoc
notions. Nothing rigourous here.

Closed virtual particle loops in the vacuum are a well-known phenomenon in
perturbation approaches to QFT, but because of energy conservation, these
loops are strictly of zero energy-momentum. Since they are not coupled to
anything, so they do not affect any measurable physics. At most they add an
overall undetectable phase to the wave function.

Bruce

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Re: The size of the universe

2020-06-08 Thread smitra

On 07-06-2020 01:16, Bruce Kellett wrote:

On Sat, Jun 6, 2020 at 11:54 PM smitra wrote:

On 06-06-2020 01:07, Bruce Kellett wrote:

On Sat, Jun 6, 2020 at 3:11 AM smitra wrote:

These fluctuations at zero temperature are what we call "quantum
fluctuations"
in physics.

I think you are confusing the zero point energy of quantum fields

with

"quantum fluctuations". The zero point energy, whatever it might

be,

does not "fluctuate". "Fluctuate means change with time, and the

zero

point energy is just a value, and it does not change with time --

does not "fluctuate".

While one can argue about the word "fluctuation" used here, what
matters
is that the field strength will take on random values when measured
in
the ground state.

OK, so nothing actually "fluctuates": it is just that measurement
gives random values. That is what the standard deviation or variance
is actually about -- the statistical scatter over repeated
measurements of similar systems.

I think a lot of confusion arises from statements such as this in
Wikipedia: "quantum systems constantly fluctuate in their lowest
energy state as described by the Heisenberg uncertainty principle
[1]." (Wiki article on zero point energy.) This is false, because the
HUP again refers to results from repeated measurements, not intrinsic
variation in the state.

Yes, I agree with this.

Applying the idea of quantum fluctuations to the inflaton field is a
mistake, since inflation is based on a classical field. And you do not
quantize a classical field by adding "quantum fluctuations".

It's an approximate way to do computations that can be justified
rigorously, see e.g. these lecture notes:

https://www.nikhef.nl/~mpostma/inflation.pdf

section 3 on page 15 and further.

Jason was

claiming that quantum fluctuations in the energy of the inflaton field
caused variation in the time of exit from inflation, and this led to
the density perturbations. Such a model is incorrect. To get density
variations, you have to have variations in energy density. And these
cannot be "quantum fluctuations", because energy is conserved in all
quantum interactions -- given a state of a particular energy, that
energy does not fluctuate.

There are fluctuations in the local energy density, and there is also
nontrivial correlation between the local energy density at two different
points. But I was wrong about the average of the filed vanishing. While
that's generally true, i case of the inflaton, a local fluctuation in
the field average is going to be stretched out so much that the entire
region inside the horizon gets a nonzero value for the field.

Variation between different measurements
can arise only if the original state is a superposition of components
of different basic energy, and that state is then repeatedly measured.
That does not happen in inflation.

No, there is not. It is entirely ad hoc. The problem stems from the
fact that the scalar inflaton field has the dimensions of energy, so,
because energy is strictly conserved, the field value cannot
fluctuate.

It's not ad hoc, it's all explained here:

https://www.nikhef.nl/~mpostma/inflation.pdf

Saibal

Re: The size of the universe

2020-06-07 Thread Bruno Marchal



> On 6 Jun 2020, at 16:34, smitra  wrote:
> 
> On 06-06-2020 12:57, Bruno Marchal wrote:
>>> On 5 Jun 2020, at 19:11, smitra  wrote:
>>> On 05-06-2020 18:07, Jason Resch wrote:
 On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett 
 wrote:
> On Fri, Jun 5, 2020 at 7:16 PM Jason Resch 
> wrote:
> On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett 
> wrote:
> On Tue, Jun 2, 2020 at 9:59 AM Jason Resch 
> wrote:
> On Monday, June 1, 2020, Bruce Kellett 
> wrote:
> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch 
> wrote:
> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
> wrote:
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
> I recently wrote an article on the size of the universe and the
> scope of reality:
> https://alwaysasking.com/how-big-is-the-universe/
> It's first of what I hope will be a series of articles which are
> largely inspired by some of the conversations I've enjoyed here. It
> covers many topics including the historic discoveries, the big bang,
> inflation, string theory, and mathematical realism.
> Jason
> I see you agree with the MUH that there are infinite, identical
> repeats of any universe.
 To be clear, the MUH is separate theory from the idea of a spatially
 infinite universe (which is just the standard cosmological model that
 working cosmologists assume today, that the universe is infinite,
 homogeneous, and seeded by random quantum fluctuations occurring at
 all scales during the expansion of the universe).
 Define what you mean by "quantum fluctuations". There are no such
 things in standard quantum mechanics.
 Variations in the decay of the inflaton field that seeded the
 variations in density that led to stars and galaxies, and confirmed by
 observations by COBE and Planck.
 That is not how inflation models work.
 Are you sure about that? If so could you explain the error in this or
 in my understanding of it:
 https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
 You video gives an oversimplified comic-book version of inflation. If
 you want to understand inflation, you have to go to a professional,
 expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys.
 78:537-589 (2006). (Also in arXiv:0507632). You will see from this
 that density perturbations are just Guassian random fields, put in by
 hand, with parameters adjusted to fit the data. There are no intrinsic
 "quantum fluctuations".
 According to the theory what is the source of this gaussian
 randomnesses? What makes a field random if not quantum mechanics?
 Jason
>>> There obviously do exist quantum fluctuations. A down to Earth example is 
>>> Johnson noise. Connect a sensitive voltmeter to a resistor and you'll 
>>> detect fluctuations in the voltage. The average voltage is zero, but there 
>>> are fluctuations due to thermal motion of the electrons. If you cool down 
>>> the resistor these fluctuations will become smaller, but even at absolute 
>>> zero there will still be fluctuations in the voltage. These fluctuations at 
>>> zero temperature are what we call "quantum fluctuations" in physics. Now I 
>>> remember an old discussion with Bruce on this list about this, and insisted 
>>> that what I called quantum fluctuations are actually "thermal fluctuations 
>>> at 0 K". But at 0 K the system is in the ground state, so it doesn't matter 
>>> what you name you give to the fluctuations, these are purely quantum 
>>> mechanical in nature, they don't arise from an initial randomness in the 
>>> initial state.
>> Eventually, they do arise from the fact that no universal machine can
>> know in which history she belongs, and that even the physical void is
>> a phenomenological product of infinitely many computations. Actually,
>> when we assume Mechanism.
> 
> 
> It seems plausible to me that one should be able to derive quantum mechanics 
> from such ideas involving some form of a mathematical multiverse.

The theorem in metaphysics is that if Digital Mechanism is true, the 
“multiverse” ontology is limited to elementary arithmetic, which execute all 
computations (as we know since the 1930s). Church’s thesis makes this notion of 
“whole” quite solid, and formalism independent.

But it is more a multi-dream or multi-histories (a machine first person plural 
construct) than a multi-world, or multi-universe (which is rarely well 
defined). Yet, the physical phenomenology might have a distinctive look of 
quantum multiverse, but there too, the universes are only apparent, and do not 
belong to the ontology. (Like God and the Noùs in Plotinus).




> The multiverse aspect of the MWI is likely correct but it's problematic when 
> considering the detailed physics.

I am not sure which problems you allude too. It is very complex, but if 
Mechanism is true, it is the only way to get both the quanta right, and the 
qualia right.

Re: The size of the universe

2020-06-07 Thread Bruce Kellett

On Sun, Jun 7, 2020 at 4:37 PM Jason Resch  wrote:

> On Sun, Jun 7, 2020 at 12:39 AM Bruce Kellett 
> wrote:
>
>> On Sun, Jun 7, 2020 at 3:13 PM Jason Resch  wrote:
>>
>>>
>>> When you look up at the sky you are indirectly performing a measurement
>>> of the inflaton field's energy in different parts of the early universe.
>>>
>>
>>
>> That is the mythology that remains to be explained. Energy conservation
>> forbids fluctuations in the energy density of the inflaton field.
>>
>>
> Uncertainty implies you can't know the energy density exactly, does it not?
>

Not really. If you mean the HUP, then it doesn't imply this at all. If you
mean merely that we are ignorant about the energy density at different
places, then maybe. But you then have to explain these energy differences.
The problem is that the inflation models tend to have a classical inflaton
field, and that is not a superposition of anything.

Accordingly, wouldn't measurements of it at different places and times
> yield differing results?
>

The only way for this to happen in QM is if the initial state is a
superposition of different energy states. You then have the problem of
explaining exactly what you mean by a measurement of these states in this
context. If you read the paper I referenced, you see that at the end of
inflation, the temperature everywhere was exactly zero, so there are no
thermal fluctuations. Any variations in the energy density over the
universe must, therefore, have been frozen in during the inflation period.
Reheating after the end of inflation is a whole other problem.

Bruce

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Re: The size of the universe

2020-06-07 Thread Jason Resch

On Sun, Jun 7, 2020 at 12:39 AM Bruce Kellett  wrote:

> On Sun, Jun 7, 2020 at 3:13 PM Jason Resch  wrote:
>
>> On Saturday, June 6, 2020, Bruce Kellett  wrote:
>>
>>> On Sat, Jun 6, 2020 at 11:54 PM smitra  wrote:
>>>
 On 06-06-2020 01:07, Bruce Kellett wrote:
 > On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:

 >> These fluctuations at zero temperature are what we call "quantum
 >> fluctuations"
 >> in physics.
 >
 > I think you are confusing the zero point energy of quantum fields with
 > "quantum fluctuations". The zero point energy, whatever it might be,
 > does not "fluctuate". "Fluctuate means change with time, and the zero
 > point energy is just a value, and it does not change with time -- it
 > does not "fluctuate".

 The ground state energy does not fluctuate, but other observables such
 as the field strengths obviously do in the sense of having a variance.
 The energy is quadratic in the field and this has nonzero expectation
 value, while the expectation value of the field will usually be zero.
 So, one can say that the zero point energy represents the quantum
 fluctuations of the field, because it is the variance of the field.
 While one can argue about the word "fluctuation" used here, what
 matters
 is that the field strength will take on random values when measured in
 the ground state.
>>>
>>>
>>>
>>> OK, so nothing actually "fluctuates": it is just that measurement gives
>>> random values. That is what the standard deviation or variance is actually
>>> about -- the statistical scatter over repeated measurements of similar
>>> systems.
>>>
>>> I think a lot of confusion arises from statements such as this in
>>> Wikipedia: "quantum systems constantly fluctuate in their lowest energy
>>> state as described by the Heisenberg uncertainty principle
>>> ."
>>> (Wiki article on zero point energy.) This is false, because the HUP
>>> again refers to results from repeated measurements, not intrinsic variation
>>> in the state.
>>>
>>> Applying the idea of quantum fluctuations to the inflaton field is a
>>> mistake, since inflation is based on a classical field. And you do not
>>> quantize a classical field by adding "quantum fluctuations". Jason was
>>> claiming that quantum fluctuations in the energy of the inflaton field
>>> caused variation in the time of exit from inflation, and this led to the
>>> density perturbations. Such a model is incorrect. To get density
>>> variations, you have to have variations in energy density. And these cannot
>>> be "quantum fluctuations", because energy is conserved in all quantum
>>> interactions -- given a state of a particular energy, that energy does not
>>> fluctuate. Variation between different measurements can arise only if the
>>> original state is a superposition of components of different basic energy,
>>> and that state is then repeatedly measured. That does not happen in
>>> inflation.
>>>
>>
>> When you look up at the sky you are indirectly performing a measurement
>> of the inflaton field's energy in different parts of the early universe.
>>
>
>
> That is the mythology that remains to be explained. Energy conservation
> forbids fluctuations in the energy density of the inflaton field.
>
>
Uncertainty implies you can't know the energy density exactly, does it not?
Accordingly, wouldn't measurements of it at different places and times
yield differing results?

Jason

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Re: The size of the universe

2020-06-06 Thread Bruce Kellett

On Sun, Jun 7, 2020 at 3:13 PM Jason Resch  wrote:

> On Saturday, June 6, 2020, Bruce Kellett  wrote:
>
>> On Sat, Jun 6, 2020 at 11:54 PM smitra  wrote:
>>
>>> On 06-06-2020 01:07, Bruce Kellett wrote:
>>> > On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:
>>>
>>> >> These fluctuations at zero temperature are what we call "quantum
>>> >> fluctuations"
>>> >> in physics.
>>> >
>>> > I think you are confusing the zero point energy of quantum fields with
>>> > "quantum fluctuations". The zero point energy, whatever it might be,
>>> > does not "fluctuate". "Fluctuate means change with time, and the zero
>>> > point energy is just a value, and it does not change with time -- it
>>> > does not "fluctuate".
>>>
>>> The ground state energy does not fluctuate, but other observables such
>>> as the field strengths obviously do in the sense of having a variance.
>>> The energy is quadratic in the field and this has nonzero expectation
>>> value, while the expectation value of the field will usually be zero.
>>> So, one can say that the zero point energy represents the quantum
>>> fluctuations of the field, because it is the variance of the field.
>>> While one can argue about the word "fluctuation" used here, what matters
>>> is that the field strength will take on random values when measured in
>>> the ground state.
>>
>>
>>
>> OK, so nothing actually "fluctuates": it is just that measurement gives
>> random values. That is what the standard deviation or variance is actually
>> about -- the statistical scatter over repeated measurements of similar
>> systems.
>>
>> I think a lot of confusion arises from statements such as this in
>> Wikipedia: "quantum systems constantly fluctuate in their lowest energy
>> state as described by the Heisenberg uncertainty principle
>> ." (Wiki
>> article on zero point energy.) This is false, because the HUP again
>> refers to results from repeated measurements, not intrinsic variation in
>> the state.
>>
>> Applying the idea of quantum fluctuations to the inflaton field is a
>> mistake, since inflation is based on a classical field. And you do not
>> quantize a classical field by adding "quantum fluctuations". Jason was
>> claiming that quantum fluctuations in the energy of the inflaton field
>> caused variation in the time of exit from inflation, and this led to the
>> density perturbations. Such a model is incorrect. To get density
>> variations, you have to have variations in energy density. And these cannot
>> be "quantum fluctuations", because energy is conserved in all quantum
>> interactions -- given a state of a particular energy, that energy does not
>> fluctuate. Variation between different measurements can arise only if the
>> original state is a superposition of components of different basic energy,
>> and that state is then repeatedly measured. That does not happen in
>> inflation.
>>
>
> When you look up at the sky you are indirectly performing a measurement of
> the inflaton field's energy in different parts of the early universe.
>


That is the mythology that remains to be explained. Energy conservation
forbids fluctuations in the energy density of the inflaton field.

Bruce

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Re: The size of the universe

2020-06-06 Thread Jason Resch

On Saturday, June 6, 2020, Bruce Kellett  wrote:

> On Sat, Jun 6, 2020 at 11:54 PM smitra  wrote:
>
>> On 06-06-2020 01:07, Bruce Kellett wrote:
>> > On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:
>>
>> >> These fluctuations at zero temperature are what we call "quantum
>> >> fluctuations"
>> >> in physics.
>> >
>> > I think you are confusing the zero point energy of quantum fields with
>> > "quantum fluctuations". The zero point energy, whatever it might be,
>> > does not "fluctuate". "Fluctuate means change with time, and the zero
>> > point energy is just a value, and it does not change with time -- it
>> > does not "fluctuate".
>>
>> The ground state energy does not fluctuate, but other observables such
>> as the field strengths obviously do in the sense of having a variance.
>> The energy is quadratic in the field and this has nonzero expectation
>> value, while the expectation value of the field will usually be zero.
>> So, one can say that the zero point energy represents the quantum
>> fluctuations of the field, because it is the variance of the field.
>> While one can argue about the word "fluctuation" used here, what matters
>> is that the field strength will take on random values when measured in
>> the ground state.
>
>
>
> OK, so nothing actually "fluctuates": it is just that measurement gives
> random values. That is what the standard deviation or variance is actually
> about -- the statistical scatter over repeated measurements of similar
> systems.
>
> I think a lot of confusion arises from statements such as this in
> Wikipedia: "quantum systems constantly fluctuate in their lowest energy
> state as described by the Heisenberg uncertainty principle
> ." (Wiki
> article on zero point energy.) This is false, because the HUP again
> refers to results from repeated measurements, not intrinsic variation in
> the state.
>
> Applying the idea of quantum fluctuations to the inflaton field is a
> mistake, since inflation is based on a classical field. And you do not
> quantize a classical field by adding "quantum fluctuations". Jason was
> claiming that quantum fluctuations in the energy of the inflaton field
> caused variation in the time of exit from inflation, and this led to the
> density perturbations. Such a model is incorrect. To get density
> variations, you have to have variations in energy density. And these cannot
> be "quantum fluctuations", because energy is conserved in all quantum
> interactions -- given a state of a particular energy, that energy does not
> fluctuate. Variation between different measurements can arise only if the
> original state is a superposition of components of different basic energy,
> and that state is then repeatedly measured. That does not happen in
> inflation.
>

When you look up at the sky you are indirectly performing a measurement of
the inflaton field's energy in different parts of the early universe.

Jason


>
>
>
>> It is this phenomena what Jason referred to. In the
>> scientific papers on inflation they may go about computing the effects
>> of the fluctuations in a semi-classical way by putting in the
>> fluctuations by hand in classical equations of motion, but there is a
>> solid theoretical basis for such an approach.
>>
>
> No, there is not. It is entirely ad hoc. The problem stems from the fact
> that the scalar inflaton field has the dimensions of energy, so, because
> energy is strictly conserved, the field value cannot fluctuate.
>
> Bruce
>
> --
> You received this message because you are subscribed to the Google Groups
> "Everything List" group.
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> email to everything-list+unsubscr...@googlegroups.com.
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> msgid/everything-list/CAFxXSLSj_aLCpD-m9iu71hXoJVoWWb9aEXBOnfa83B78o
> ZkTEQ%40mail.gmail.com
> 
> .
>

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Re: The size of the universe

2020-06-06 Thread Bruce Kellett

On Sat, Jun 6, 2020 at 11:54 PM smitra  wrote:

> On 06-06-2020 01:07, Bruce Kellett wrote:
> > On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:
>
> >> These fluctuations at zero temperature are what we call "quantum
> >> fluctuations"
> >> in physics.
> >
> > I think you are confusing the zero point energy of quantum fields with
> > "quantum fluctuations". The zero point energy, whatever it might be,
> > does not "fluctuate". "Fluctuate means change with time, and the zero
> > point energy is just a value, and it does not change with time -- it
> > does not "fluctuate".
>
> The ground state energy does not fluctuate, but other observables such
> as the field strengths obviously do in the sense of having a variance.
> The energy is quadratic in the field and this has nonzero expectation
> value, while the expectation value of the field will usually be zero.
> So, one can say that the zero point energy represents the quantum
> fluctuations of the field, because it is the variance of the field.
> While one can argue about the word "fluctuation" used here, what matters
> is that the field strength will take on random values when measured in
> the ground state.

OK, so nothing actually "fluctuates": it is just that measurement gives
random values. That is what the standard deviation or variance is actually
about -- the statistical scatter over repeated measurements of similar
systems.

I think a lot of confusion arises from statements such as this in
Wikipedia: "quantum systems constantly fluctuate in their lowest energy
state as described by the Heisenberg uncertainty principle
." (Wiki
article on zero point energy.) This is false, because the HUP again refers
to results from repeated measurements, not intrinsic variation in the state.

Applying the idea of quantum fluctuations to the inflaton field is a
mistake, since inflation is based on a classical field. And you do not
quantize a classical field by adding "quantum fluctuations". Jason was
claiming that quantum fluctuations in the energy of the inflaton field
caused variation in the time of exit from inflation, and this led to the
density perturbations. Such a model is incorrect. To get density
variations, you have to have variations in energy density. And these cannot
be "quantum fluctuations", because energy is conserved in all quantum
interactions -- given a state of a particular energy, that energy does not
fluctuate. Variation between different measurements can arise only if the
original state is a superposition of components of different basic energy,
and that state is then repeatedly measured. That does not happen in
inflation.

> It is this phenomena what Jason referred to. In the
> scientific papers on inflation they may go about computing the effects
> of the fluctuations in a semi-classical way by putting in the
> fluctuations by hand in classical equations of motion, but there is a
> solid theoretical basis for such an approach.
>

No, there is not. It is entirely ad hoc. The problem stems from the fact
that the scalar inflaton field has the dimensions of energy, so, because
energy is strictly conserved, the field value cannot fluctuate.

Bruce

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Re: The size of the universe

2020-06-06 Thread 'Brent Meeker' via Everything List





On 6/6/2020 7:34 AM, smitra wrote:

On 06-06-2020 12:57, Bruno Marchal wrote:

On 5 Jun 2020, at 19:11, smitra  wrote:

On 05-06-2020 18:07, Jason Resch wrote:

On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett 
wrote:

On Fri, Jun 5, 2020 at 7:16 PM Jason Resch 
wrote:
On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett 
wrote:
On Tue, Jun 2, 2020 at 9:59 AM Jason Resch 
wrote:
On Monday, June 1, 2020, Bruce Kellett 
wrote:
On Tue, Jun 2, 2020 at 5:39 AM Jason Resch 
wrote:
On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
wrote:
On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
I recently wrote an article on the size of the universe and the
scope of reality:
https://alwaysasking.com/how-big-is-the-universe/
It's first of what I hope will be a series of articles which are
largely inspired by some of the conversations I've enjoyed here. It
covers many topics including the historic discoveries, the big bang,
inflation, string theory, and mathematical realism.
Jason
I see you agree with the MUH that there are infinite, identical
repeats of any universe.

To be clear, the MUH is separate theory from the idea of a spatially
infinite universe (which is just the standard cosmological model that
working cosmologists assume today, that the universe is infinite,
homogeneous, and seeded by random quantum fluctuations occurring at
all scales during the expansion of the universe).
Define what you mean by "quantum fluctuations". There are no such
things in standard quantum mechanics.
Variations in the decay of the inflaton field that seeded the
variations in density that led to stars and galaxies, and confirmed by
observations by COBE and Planck.
That is not how inflation models work.
Are you sure about that? If so could you explain the error in this or
in my understanding of it:
https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
You video gives an oversimplified comic-book version of inflation. If
you want to understand inflation, you have to go to a professional,
expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys.
78:537-589 (2006). (Also in arXiv:0507632). You will see from this
that density perturbations are just Guassian random fields, put in by
hand, with parameters adjusted to fit the data. There are no intrinsic
"quantum fluctuations".
According to the theory what is the source of this gaussian
randomnesses? What makes a field random if not quantum mechanics?
Jason


There obviously do exist quantum fluctuations. A down to Earth 
example is Johnson noise. Connect a sensitive voltmeter to a 
resistor and you'll detect fluctuations in the voltage. The average 
voltage is zero, but there are fluctuations due to thermal motion of 
the electrons. If you cool down the resistor these fluctuations will 
become smaller, but even at absolute zero there will still be 
fluctuations in the voltage. These fluctuations at zero temperature 
are what we call "quantum fluctuations" in physics. Now I remember 
an old discussion with Bruce on this list about this, and insisted 
that what I called quantum fluctuations are actually "thermal 
fluctuations at 0 K". But at 0 K the system is in the ground state, 
so it doesn't matter what you name you give to the fluctuations, 
these are purely quantum mechanical in nature, they don't arise from 
an initial randomness in the initial state.


Eventually, they do arise from the fact that no universal machine can
know in which history she belongs, and that even the physical void is
a phenomenological product of infinitely many computations. Actually,
when we assume Mechanism.




It seems plausible to me that one should be able to derive quantum 
mechanics from such ideas involving some form of a mathematical 
multiverse. The multiverse aspect of the MWI is likely correct but 
it's problematic when considering the detailed physics. It's similar 
to how Einstein got the idea that gravity must be linked to curved 
space-time long before he had discovered the precise mathematical 
formulation of general relativity. Had he or someone else stuck to 
just vague ideas
then critics would have thrashed the whole idea of curved space-time, 
and they would worked with retarded gravitational

potentials analogous to those used in electromagnetism.

Michio Kaku has said that if Einstein had not developed general 
relativity that physicists would have used such a wrong relativistic 
formalism to describe gravity, general relativity would not have been 
developed before the 1970s.


Except that Hilbert was only weeks behind Einstein in developing GR.  
Supposedly he had gotten sidetracked by trying to include EM in a 
unified theory as Kaluza and Klein did later.


Brent

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Re: The size of the universe

2020-06-06 Thread smitra

On 06-06-2020 12:57, Bruno Marchal wrote:

On 5 Jun 2020, at 19:11, smitra wrote:

On 05-06-2020 18:07, Jason Resch wrote:

On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett
wrote:

On Fri, Jun 5, 2020 at 7:16 PM Jason Resch
wrote:
On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett
wrote:
On Tue, Jun 2, 2020 at 9:59 AM Jason Resch
wrote:
On Monday, June 1, 2020, Bruce Kellett
wrote:
On Tue, Jun 2, 2020 at 5:39 AM Jason Resch
wrote:
On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson
wrote:
On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
I recently wrote an article on the size of the universe and the
scope of reality:
https://alwaysasking.com/how-big-is-the-universe/
It's first of what I hope will be a series of articles which are
largely inspired by some of the conversations I've enjoyed here. It
covers many topics including the historic discoveries, the big bang,
inflation, string theory, and mathematical realism.
Jason
I see you agree with the MUH that there are infinite, identical
repeats of any universe.

To be clear, the MUH is separate theory from the idea of a spatially
infinite universe (which is just the standard cosmological model that
working cosmologists assume today, that the universe is infinite,
homogeneous, and seeded by random quantum fluctuations occurring at
all scales during the expansion of the universe).
Define what you mean by "quantum fluctuations". There are no such
things in standard quantum mechanics.
Variations in the decay of the inflaton field that seeded the
variations in density that led to stars and galaxies, and confirmed
by

observations by COBE and Planck.
That is not how inflation models work.
Are you sure about that? If so could you explain the error in this or
in my understanding of it:
https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
You video gives an oversimplified comic-book version of inflation. If
you want to understand inflation, you have to go to a professional,
expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys.
78:537-589 (2006). (Also in arXiv:0507632). You will see from this
that density perturbations are just Guassian random fields, put in by
hand, with parameters adjusted to fit the data. There are no
intrinsic

"quantum fluctuations".
According to the theory what is the source of this gaussian
randomnesses? What makes a field random if not quantum mechanics?
Jason

There obviously do exist quantum fluctuations. A down to Earth example
is Johnson noise. Connect a sensitive voltmeter to a resistor and
you'll detect fluctuations in the voltage. The average voltage is
zero, but there are fluctuations due to thermal motion of the
electrons. If you cool down the resistor these fluctuations will
become smaller, but even at absolute zero there will still be
fluctuations in the voltage. These fluctuations at zero temperature
are what we call "quantum fluctuations" in physics. Now I remember an
old discussion with Bruce on this list about this, and insisted that
what I called quantum fluctuations are actually "thermal fluctuations
at 0 K". But at 0 K the system is in the ground state, so it doesn't
matter what you name you give to the fluctuations, these are purely
quantum mechanical in nature, they don't arise from an initial
randomness in the initial state.

Eventually, they do arise from the fact that no universal machine can
know in which history she belongs, and that even the physical void is
a phenomenological product of infinitely many computations. Actually,
when we assume Mechanism.

It seems plausible to me that one should be able to derive quantum
mechanics from such ideas involving some form of a mathematical
multiverse. The multiverse aspect of the MWI is likely correct but it's
problematic when considering the detailed physics. It's similar to how
Einstein got the idea that gravity must be linked to curved space-time
long before he had discovered the precise mathematical formulation of
general relativity. Had he or someone else stuck to just vague ideas
then critics would have thrashed the whole idea of curved space-time,
and they would worked with retarded gravitational

potentials analogous to those used in electromagnetism.

Michio Kaku has said that if Einstein had not developed general
relativity that physicists would have used such a wrong relativistic
formalism to describe gravity, general relativity would not have been
developed before the 1970s.

Saibal

Re: The size of the universe

2020-06-06 Thread smitra

On 06-06-2020 01:07, Bruce Kellett wrote:

On Sat, Jun 6, 2020 at 3:11 AM smitra wrote:

there are fluctuations due to thermal motion of the electrons. If
you
cool down the resistor these fluctuations will become smaller, but
even
at absolute zero there will still be fluctuations in the voltage.

Can you point to experimental evidence of this? As far as I know,
absolute zero temperature is intrinsically unattainable.

There exists a vast literature on detectors that operate in the regime
where most of the noise is due to quantum effects rather than thermal
effects.

These fluctuations at zero temperature are what we call "quantum
fluctuations"
in physics.

I think you are confusing the zero point energy of quantum fields with
"quantum fluctuations". The zero point energy, whatever it might be,
does not "fluctuate". "Fluctuate means change with time, and the zero
point energy is just a value, and it does not change with time -- it
does not "fluctuate".

The ground state energy does not fluctuate, but other observables such
as the field strengths obviously do in the sense of having a variance.
The energy is quadratic in the field and this has nonzero expectation
value, while the expectation value of the field will usually be zero.
So, one can say that the zero point energy represents the quantum
fluctuations of the field, because it is the variance of the field.
While one can argue about the word "fluctuation" used here, what matters
is that the field strength will take on random values when measured in
the ground state. It is this phenomena what Jason referred to. In the
scientific papers on inflation they may go about computing the effects
of the fluctuations in a semi-classical way by putting in the
fluctuations by hand in classical equations of motion, but there is a
solid theoretical basis for such an approach.

Saibal

Re: The size of the universe

2020-06-06 Thread Bruno Marchal



> On 5 Jun 2020, at 19:11, smitra  wrote:
> 
> On 05-06-2020 18:07, Jason Resch wrote:
>> On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett 
>> wrote:
>>> On Fri, Jun 5, 2020 at 7:16 PM Jason Resch 
>>> wrote:
>>> On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett 
>>> wrote:
>>> On Tue, Jun 2, 2020 at 9:59 AM Jason Resch 
>>> wrote:
>>> On Monday, June 1, 2020, Bruce Kellett 
>>> wrote:
>>> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch 
>>> wrote:
>>> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
>>> wrote:
>>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>> I recently wrote an article on the size of the universe and the
>>> scope of reality:
>>> https://alwaysasking.com/how-big-is-the-universe/
>>> It's first of what I hope will be a series of articles which are
>>> largely inspired by some of the conversations I've enjoyed here. It
>>> covers many topics including the historic discoveries, the big bang,
>>> inflation, string theory, and mathematical realism.
>>> Jason
>>> I see you agree with the MUH that there are infinite, identical
>>> repeats of any universe.
>> To be clear, the MUH is separate theory from the idea of a spatially
>> infinite universe (which is just the standard cosmological model that
>> working cosmologists assume today, that the universe is infinite,
>> homogeneous, and seeded by random quantum fluctuations occurring at
>> all scales during the expansion of the universe).
>> Define what you mean by "quantum fluctuations". There are no such
>> things in standard quantum mechanics.
>> Variations in the decay of the inflaton field that seeded the
>> variations in density that led to stars and galaxies, and confirmed by
>> observations by COBE and Planck.
>> That is not how inflation models work.
>> Are you sure about that? If so could you explain the error in this or
>> in my understanding of it:
>> https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
>> You video gives an oversimplified comic-book version of inflation. If
>> you want to understand inflation, you have to go to a professional,
>> expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys.
>> 78:537-589 (2006). (Also in arXiv:0507632). You will see from this
>> that density perturbations are just Guassian random fields, put in by
>> hand, with parameters adjusted to fit the data. There are no intrinsic
>> "quantum fluctuations".
>> According to the theory what is the source of this gaussian
>> randomnesses? What makes a field random if not quantum mechanics?
>> Jason
> 
> There obviously do exist quantum fluctuations. A down to Earth example is 
> Johnson noise. Connect a sensitive voltmeter to a resistor and you'll detect 
> fluctuations in the voltage. The average voltage is zero, but there are 
> fluctuations due to thermal motion of the electrons. If you cool down the 
> resistor these fluctuations will become smaller, but even at absolute zero 
> there will still be fluctuations in the voltage. These fluctuations at zero 
> temperature are what we call "quantum fluctuations" in physics. Now I 
> remember an old discussion with Bruce on this list about this, and insisted 
> that what I called quantum fluctuations are actually "thermal fluctuations at 
> 0 K". But at 0 K the system is in the ground state, so it doesn't matter what 
> you name you give to the fluctuations, these are purely quantum mechanical in 
> nature, they don't arise from an initial randomness in the initial state.

Eventually, they do arise from the fact that no universal machine can know in 
which history she belongs, and that even the physical void is a 
phenomenological product of infinitely many computations. Actually, when we 
assume Mechanism.

Bruno

> 
> Saibal
> 
> -- 
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Re: The size of the universe

2020-06-05 Thread Alan Grayson



On Friday, June 5, 2020 at 7:31:56 PM UTC-6, Alan Grayson wrote:
>
>
>
> On Friday, June 5, 2020 at 5:07:58 PM UTC-6, Bruce wrote:
>>
>> On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:
>>
>>>
>>> There obviously do exist quantum fluctuations. A down to Earth example 
>>> is Johnson noise. Connect a sensitive voltmeter to a resistor and you'll 
>>> detect fluctuations in the voltage. The average voltage is zero, but 
>>> there are fluctuations due to thermal motion of the electrons. If you 
>>> cool down the resistor these fluctuations will become smaller, but even 
>>> at absolute zero there will still be fluctuations in the voltage.
>>
>>
>>
>> Can you point to experimental evidence of this? As far as I know, 
>> absolute zero temperature is intrinsically unattainable.
>>
>>
>> These fluctuations at zero temperature are what we call "quantum 
>>> fluctuations" 
>>> in physics.
>>
>>
>>  
>> I think you are confusing the zero point energy of quantum fields with 
>> "quantum fluctuations". The zero point energy, whatever it might be, does 
>> not "fluctuate". "Fluctuate means change with time, and the zero point 
>> energy is just a value, and it does not change with time -- it does not 
>> "fluctuate".
>>
>
> Another point worth mentioning is that when a quantum system is measured, 
> we get some specific eigenvalue. And if THAT system is measured again, the 
> measured value remains the same. No fluctuation. (I forget exactly why 
> that's the case.). But if we measure a different system represented by the 
> same wave function, the measured value changes. So the message is, again, 
> that no single system fluctuates. AG 
>

Oh, now I recall.  After the measurement, the system's state is the 
eigenfunction of the eigenvalue measured. Previously, it was in a 
superposition of states. So when we measure that specific system again, the 
probability of measuring the same eigenvalue is unity. AG 

>
>> Bruce
>>
>>
>> Now I remember an old discussion with Bruce on this list 
>>> about this, and insisted that what I called quantum fluctuations are 
>>> actually "thermal fluctuations at 0 K". But at 0 K the system is in the 
>>> ground state, so it doesn't matter what you name you give to the 
>>> fluctuations, these are purely quantum mechanical in nature, they don't 
>>> arise from an initial randomness in the initial state.
>>>
>>> Saibal
>>>
>>

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Re: The size of the universe

2020-06-05 Thread Alan Grayson



On Friday, June 5, 2020 at 5:07:58 PM UTC-6, Bruce wrote:
>
> On Sat, Jun 6, 2020 at 3:11 AM smitra > 
> wrote:
>
>>
>> There obviously do exist quantum fluctuations. A down to Earth example 
>> is Johnson noise. Connect a sensitive voltmeter to a resistor and you'll 
>> detect fluctuations in the voltage. The average voltage is zero, but 
>> there are fluctuations due to thermal motion of the electrons. If you 
>> cool down the resistor these fluctuations will become smaller, but even 
>> at absolute zero there will still be fluctuations in the voltage.
>
>
>
> Can you point to experimental evidence of this? As far as I know, absolute 
> zero temperature is intrinsically unattainable.
>
>
> These fluctuations at zero temperature are what we call "quantum 
>> fluctuations" 
>> in physics.
>
>
>  
> I think you are confusing the zero point energy of quantum fields with 
> "quantum fluctuations". The zero point energy, whatever it might be, does 
> not "fluctuate". "Fluctuate means change with time, and the zero point 
> energy is just a value, and it does not change with time -- it does not 
> "fluctuate".
>

Another point worth mentioning is that when a quantum system is measured, 
we get some specific eigenvalue. And if THAT system is measured again, the 
measured value remains the same. No fluctuation. (I forget exactly why 
that's the case.). But if we measure a different system represented by the 
same wave function, the measured value changes. So the message is, again, 
that no single system fluctuates. AG 

>
> Bruce
>
>
> Now I remember an old discussion with Bruce on this list 
>> about this, and insisted that what I called quantum fluctuations are 
>> actually "thermal fluctuations at 0 K". But at 0 K the system is in the 
>> ground state, so it doesn't matter what you name you give to the 
>> fluctuations, these are purely quantum mechanical in nature, they don't 
>> arise from an initial randomness in the initial state.
>>
>> Saibal
>>
>

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Re: The size of the universe

2020-06-05 Thread Bruce Kellett

On Sat, Jun 6, 2020 at 2:08 AM Jason Resch  wrote:

> On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett  wrote:
>
>>
>> You video gives an oversimplified comic-book version of inflation. If you
>> want to understand inflation, you have to go to a professional, expert
>> review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys. 78:537-589
>> (2006). (Also in arXiv:0507632). You will see from this that density
>> perturbations are just Guassian random fields, put in by hand, with
>> parameters adjusted to fit the data. There are no intrinsic "quantum
>> fluctuations".
>>
>
>
> According to the theory what is the source of this gaussian randomnesses?
> What makes a field random if not quantum mechanics?
>

There is no theory behind this -- the gaussian "fluctuations" are just put
in by hand. There is the unspoken implication that the origin of these
fluctuations is quantum, but there is no theory for this, and, as has been
pointed out, there are no such things as "quantum fluctuations" in this
sense. Tim Maudlin has commented on this in Sabine Hossenfelder's blog:

https://www.blogger.com/comment.g?blogID=22973357=264282891971221826

Bruce

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Re: The size of the universe

2020-06-05 Thread Bruce Kellett

On Sat, Jun 6, 2020 at 3:11 AM smitra  wrote:

>
> There obviously do exist quantum fluctuations. A down to Earth example
> is Johnson noise. Connect a sensitive voltmeter to a resistor and you'll
> detect fluctuations in the voltage. The average voltage is zero, but
> there are fluctuations due to thermal motion of the electrons. If you
> cool down the resistor these fluctuations will become smaller, but even
> at absolute zero there will still be fluctuations in the voltage.



Can you point to experimental evidence of this? As far as I know, absolute
zero temperature is intrinsically unattainable.


These fluctuations at zero temperature are what we call "quantum
> fluctuations"
> in physics.



I think you are confusing the zero point energy of quantum fields with
"quantum fluctuations". The zero point energy, whatever it might be, does
not "fluctuate". "Fluctuate means change with time, and the zero point
energy is just a value, and it does not change with time -- it does not
"fluctuate".

Bruce


Now I remember an old discussion with Bruce on this list
> about this, and insisted that what I called quantum fluctuations are
> actually "thermal fluctuations at 0 K". But at 0 K the system is in the
> ground state, so it doesn't matter what you name you give to the
> fluctuations, these are purely quantum mechanical in nature, they don't
> arise from an initial randomness in the initial state.
>
> Saibal
>

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Re: The size of the universe

2020-06-05 Thread smitra

On 05-06-2020 18:07, Jason Resch wrote:

On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett
wrote:

On Fri, Jun 5, 2020 at 7:16 PM Jason Resch
wrote:

On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett
wrote:

On Tue, Jun 2, 2020 at 9:59 AM Jason Resch
wrote:

On Monday, June 1, 2020, Bruce Kellett
wrote:

On Tue, Jun 2, 2020 at 5:39 AM Jason Resch
wrote:

On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson
wrote:

On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
I recently wrote an article on the size of the universe and the
scope of reality:
https://alwaysasking.com/how-big-is-the-universe/

It's first of what I hope will be a series of articles which are
largely inspired by some of the conversations I've enjoyed here. It
covers many topics including the historic discoveries, the big bang,
inflation, string theory, and mathematical realism.

Jason

I see you agree with the MUH that there are infinite, identical
repeats of any universe.

Define what you mean by "quantum fluctuations". There are no such
things in standard quantum mechanics.

Variations in the decay of the inflaton field that seeded the
variations in density that led to stars and galaxies, and confirmed by
observations by COBE and Planck.

That is not how inflation models work.

Are you sure about that? If so could you explain the error in this or
in my understanding of it:
https://www.youtube.com/watch?v=chsLw2siRW0=6m43s

You video gives an oversimplified comic-book version of inflation. If
you want to understand inflation, you have to go to a professional,
expert review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys.
78:537-589 (2006). (Also in arXiv:0507632). You will see from this
that density perturbations are just Guassian random fields, put in by
hand, with parameters adjusted to fit the data. There are no intrinsic
"quantum fluctuations".

According to the theory what is the source of this gaussian
randomnesses? What makes a field random if not quantum mechanics?

Jason

There obviously do exist quantum fluctuations. A down to Earth example
is Johnson noise. Connect a sensitive voltmeter to a resistor and you'll
detect fluctuations in the voltage. The average voltage is zero, but
there are fluctuations due to thermal motion of the electrons. If you
cool down the resistor these fluctuations will become smaller, but even
at absolute zero there will still be fluctuations in the voltage. These
fluctuations at zero temperature are what we call "quantum fluctuations"
in physics. Now I remember an old discussion with Bruce on this list
about this, and insisted that what I called quantum fluctuations are
actually "thermal fluctuations at 0 K". But at 0 K the system is in the
ground state, so it doesn't matter what you name you give to the
fluctuations, these are purely quantum mechanical in nature, they don't
arise from an initial randomness in the initial state.

Saibal

Re: The size of the universe

2020-06-05 Thread Jason Resch

On Fri, Jun 5, 2020, 5:55 AM Bruce Kellett  wrote:

> On Fri, Jun 5, 2020 at 7:16 PM Jason Resch  wrote:
>
>> On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett 
>> wrote:
>>
>>> On Tue, Jun 2, 2020 at 9:59 AM Jason Resch  wrote:
>>>
 On Monday, June 1, 2020, Bruce Kellett  wrote:

> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch 
> wrote:
>
>> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
>> wrote:
>>
>>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:

 I recently wrote an article on the size of the universe and the
 scope of reality:
 https://alwaysasking.com/how-big-is-the-universe/

 It's first of what I hope will be a series of articles which are
 largely inspired by some of the conversations I've enjoyed here. It 
 covers
 many topics including the historic discoveries, the big bang, 
 inflation,
 string theory, and mathematical realism.

 Jason

>>>
>>> I see you agree with the MUH that there are infinite, identical
>>> repeats of any universe.
>>>
>>
>> To be clear, the MUH is separate theory from the idea of a spatially
>> infinite universe (which is just the standard cosmological model that
>> working cosmologists assume today, that the universe is infinite,
>> homogeneous, and seeded by random quantum fluctuations occurring at all
>> scales during the expansion of the universe).
>>
>
>
> Define what you mean by "quantum fluctuations". There are no such
> things in standard quantum mechanics.
>
>
 Variations in the decay of the inflaton field that seeded the
 variations in density that led to stars and galaxies, and confirmed by
 observations by COBE and Planck.

>>>
>>>
>>> That is not how inflation models work.
>>>
>>
>> Are you sure about that? If so could you explain the error in this or in
>> my understanding of it:
>> https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
>>
>
>
> You video gives an oversimplified comic-book version of inflation. If you
> want to understand inflation, you have to go to a professional, expert
> review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys. 78:537-589
> (2006). (Also in arXiv:0507632). You will see from this that density
> perturbations are just Guassian random fields, put in by hand, with
> parameters adjusted to fit the data. There are no intrinsic "quantum
> fluctuations".
>


According to the theory what is the source of this gaussian randomnesses?
What makes a field random if not quantum mechanics?

Jason


> Bruce
>
> --
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> 
> .
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Re: The size of the universe

2020-06-05 Thread Bruce Kellett

On Fri, Jun 5, 2020 at 7:16 PM Jason Resch  wrote:

> On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett 
> wrote:
>
>> On Tue, Jun 2, 2020 at 9:59 AM Jason Resch  wrote:
>>
>>> On Monday, June 1, 2020, Bruce Kellett  wrote:
>>>
 On Tue, Jun 2, 2020 at 5:39 AM Jason Resch 
 wrote:

> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
> wrote:
>
>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>>
>>> I recently wrote an article on the size of the universe and the
>>> scope of reality:
>>> https://alwaysasking.com/how-big-is-the-universe/
>>>
>>> It's first of what I hope will be a series of articles which are
>>> largely inspired by some of the conversations I've enjoyed here. It 
>>> covers
>>> many topics including the historic discoveries, the big bang, inflation,
>>> string theory, and mathematical realism.
>>>
>>> Jason
>>>
>>
>> I see you agree with the MUH that there are infinite, identical
>> repeats of any universe.
>>
>
> To be clear, the MUH is separate theory from the idea of a spatially
> infinite universe (which is just the standard cosmological model that
> working cosmologists assume today, that the universe is infinite,
> homogeneous, and seeded by random quantum fluctuations occurring at all
> scales during the expansion of the universe).
>


 Define what you mean by "quantum fluctuations". There are no such
 things in standard quantum mechanics.


>>> Variations in the decay of the inflaton field that seeded the variations
>>> in density that led to stars and galaxies, and confirmed by observations by
>>> COBE and Planck.
>>>
>>
>>
>> That is not how inflation models work.
>>
>
> Are you sure about that? If so could you explain the error in this or in
> my understanding of it:
> https://www.youtube.com/watch?v=chsLw2siRW0=6m43s
>


You video gives an oversimplified comic-book version of inflation. If you
want to understand inflation, you have to go to a professional, expert
review, such as Bassett, Tsujikawa, and Wands, Rev. Mod. Phys. 78:537-589
(2006). (Also in arXiv:0507632). You will see from this that density
perturbations are just Guassian random fields, put in by hand, with
parameters adjusted to fit the data. There are no intrinsic "quantum
fluctuations".

Bruce

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Re: The size of the universe

2020-06-05 Thread Bruno Marchal


> On 2 Jun 2020, at 14:05, Alan Grayson  wrote:
> 
> 
> 
> On Tuesday, June 2, 2020 at 4:33:39 AM UTC-6, Bruno Marchal wrote:
> 
>> On 2 Jun 2020, at 03:07, Alan Grayson > 
>> wrote:
>> 
>> 
>> 
>> On Monday, June 1, 2020 at 3:58:01 PM UTC-6, Jason wrote:
>> Let's say time and space are continuous. Now lets design a stop watch that 
>> works as follows:
>> 
>> 1. Start button: shoots a photon with a wavelength of 300 nanometers down 
>> the length of a ruler.
>> 2. Stop button: raises the ruler so that the photon hits it at a certain 
>> point that we can measure.
>> 
>> Question: Even if space and time are continuous can this stop watch provide 
>> measurements of continuous/unlimited precision?
>> 
>> Answer: Due to the uncertainty principle, the location the photon cannot be 
>> determined to a location finer than the photon's wavelength. Accordingly, 
>> even if space/time are continuous, such a stop watch has a discrete 
>> time-resolution of (300 nanometers / speed of light ) ~= 10^-15 seconds. So 
>> for all practical purposes, there's no difference between this stop-watch 
>> 1.1 and 1.2 seconds after pressing 
>> "Start". Given this, can we be so sure that reality is continuous?
>> 
>> David Deutsch has speculated that the appearance of a continuum may be an 
>> artifact of living within an infinite ensemble of independently discrete 
>> realities. As we see a continuous variable evolve to reach some final state, 
>> it may be an increasing fraction of realities evolving to reach that state 
>> (with each one discretely changing). This would explain why a photon might 
>> seem to have an arbitrary polarization, or an electron some arbitrary 
>> fraction of spin, but when measured it only have one of two possible values.
>> 
>> In summary, I agree with you that a continuous reality rules out exact 
>> duplicates. But I would add that quantum mechanics says two regions of space 
>> can be so similar to each other that no one, and no experiment, even in 
>> theory, could tell the difference between them.
>> 
>> Jason
>> 
>> I don't see what measurements of similarity has to do with this issue. Fact 
>> is that if space is continuous,
> 
> That is not a fact.
> 
> The fact is you can't read plain English. Do you know what "if" means? AG
>  
> The fact is that we don’t know,
> 
> Another fact is that our best measurements are consistent with continuity. LC 
> has posted about this. AG


You don’t quote enough. My statements were not on the “if”, but what followed. 
As I have explained many time, Mechanism enforced the presence of continuity in 
physics, and even of some non computable feature of the physical reality (and 
indeed that is why digital physicalism is self-defeating: it is always wrong, 
with or without mechanism (an hypothesis in the cognitive science, not in 
physics).

Bruno 




>  
> neither with Mechanism, nor with physics which has not yet successfully 
> explain how to marry the quantum and GR.
> 
> With mechanism, the continuum comes from the necessary random oracle of the 
> first person posts of view.
> 
> 
> 
> 
>> there cannot be any exact repetitions. And not only is position continuous, 
>> but so are other variables, which makes the case of uniqueness even 
>> stronger. And it doesn't matter whether the universe is finite or infinite 
>> in spatial extent. So from my perspective, every universe is unique 
>> (provided continuity of spatial extent exists). AG 
> 
> Better to not assume a universe, or a god, as those things are what we need 
> to explain.
> 
> Bruno
> 
> 
> 
>> 
>> On Mon, Jun 1, 2020 at 4:24 PM Alan Grayson > wrote:
>> 
>> 
>> On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:
>> 
>> 
>> On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson > wrote:
>> 
>> 
>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>> I recently wrote an article on the size of the universe and the scope of 
>> reality:
>> https://alwaysasking.com/how-big-is-the-universe/ 
>> 
>> 
>> It's first of what I hope will be a series of articles which are largely 
>> inspired by some of the conversations I've enjoyed here. It covers many 
>> topics including the historic discoveries, the big bang, inflation, string 
>> theory, and mathematical realism.
>> 
>> Jason
>> 
>> You claim, 
>> "Every very finite sequence recurs an infinite number of times precisely 
>> because Pi goes on forever." Can you prove it? AG
>> 
>> "Similarly, should space go on forever then every possible finite 
>> arrangement of matter occurs in an infinite number of locations." Even in a 
>> finite universe, assuming space is infinitely divisible, this is false IMO. 
>> For example, if we live in a finite 4 dimensional hypersphere with only one 
>> particle, it can be placed in infinitely different locations and no repeats 
>> is plausible.  AG
>> 
>> 
>> 
>> You are right, if there are continuous variables of unlimited

Re: The size of the universe

2020-06-05 Thread Jason Resch

On Mon, Jun 1, 2020 at 8:51 PM Bruce Kellett  wrote:

> On Tue, Jun 2, 2020 at 9:59 AM Jason Resch  wrote:
>
>> On Monday, June 1, 2020, Bruce Kellett  wrote:
>>
>>> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch  wrote:
>>>
 On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
 wrote:

> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>
>> I recently wrote an article on the size of the universe and the scope
>> of reality:
>> https://alwaysasking.com/how-big-is-the-universe/
>>
>> It's first of what I hope will be a series of articles which are
>> largely inspired by some of the conversations I've enjoyed here. It 
>> covers
>> many topics including the historic discoveries, the big bang, inflation,
>> string theory, and mathematical realism.
>>
>> Jason
>>
>
> I see you agree with the MUH that there are infinite, identical
> repeats of any universe.
>

 To be clear, the MUH is separate theory from the idea of a spatially
 infinite universe (which is just the standard cosmological model that
 working cosmologists assume today, that the universe is infinite,
 homogeneous, and seeded by random quantum fluctuations occurring at all
 scales during the expansion of the universe).

>>>
>>>
>>> Define what you mean by "quantum fluctuations". There are no such things
>>> in standard quantum mechanics.
>>>
>>>
>> Variations in the decay of the inflaton field that seeded the variations
>> in density that led to stars and galaxies, and confirmed by observations by
>> COBE and Planck.
>>
>
>
> That is not how inflation models work.
>

Are you sure about that? If so could you explain the error in this or in my
understanding of it: https://www.youtube.com/watch?v=chsLw2siRW0=6m43s

Jason

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Re: The size of the universe

2020-06-02 Thread Alan Grayson



On Tuesday, June 2, 2020 at 4:33:39 AM UTC-6, Bruno Marchal wrote:
>
>
> On 2 Jun 2020, at 03:07, Alan Grayson > 
> wrote:
>
>
>
> On Monday, June 1, 2020 at 3:58:01 PM UTC-6, Jason wrote:
>>
>> Let's say time and space are continuous. Now lets design a stop watch 
>> that works as follows:
>>
>> 1. *Start button:* shoots a photon with a wavelength of 300 nanometers 
>> down the length of a ruler.
>> 2. *Stop button:* raises the ruler so that the photon hits it at a 
>> certain point that we can measure.
>>
>> Question: Even if space and time are continuous can this stop watch 
>> provide measurements of continuous/unlimited precision?
>>
>> Answer: Due to the uncertainty principle, the location the photon cannot 
>> be determined to a location finer than the photon's wavelength. 
>> Accordingly, even if space/time are continuous, such a stop watch has a 
>> discrete time-resolution of (300 nanometers / speed of light ) ~= 10^-15 
>> seconds. So for all practical purposes, there's no difference between this 
>> stop-watch 1.1 and 1.2 seconds 
>> after pressing "Start". Given this, can we be so sure that reality is 
>> continuous?
>>
>> David Deutsch has speculated that the appearance of a continuum may be an 
>> artifact of living within an infinite ensemble of independently discrete 
>> realities. As we see a continuous variable evolve to reach some final 
>> state, it may be an increasing fraction of realities evolving to reach that 
>> state (with each one discretely changing). This would explain why a photon 
>> might seem to have an arbitrary polarization, or an electron some arbitrary 
>> fraction of spin, but when measured it only have one of two possible values.
>>
>> In summary, I agree with you that a continuous reality rules out exact 
>> duplicates. But I would add that quantum mechanics says two regions of 
>> space can be so similar to each other that no one, and no experiment, even 
>> in theory, could tell the difference between them.
>>
>> Jason
>>
>
> I don't see what measurements of similarity has to do with this issue. 
> Fact is that if space is continuous, 
>
>
> That is not a fact.
>

*The fact is you can't read plain English. Do you know what "if" means? AG*
 

> The fact is that we don’t know, 
>

*Another fact is that our best measurements are consistent with continuity. 
LC has posted about this. AG*
 

> neither with Mechanism, nor with physics which has not yet successfully 
> explain how to marry the quantum and GR.
>
> With mechanism, the continuum comes from the necessary random oracle of 
> the first person posts of view.
>
>
>
>
> there cannot be any exact repetitions. And not only is position 
> continuous, but so are other variables, which makes the case of uniqueness 
> even stronger. And it doesn't matter whether the universe is finite or 
> infinite in spatial extent. So from my perspective, every universe is 
> unique (provided continuity of spatial extent exists). AG 
>
>
> Better to not assume a universe, or a god, as those things are what we 
> need to explain.
>
> Bruno
>
>
>
>
>> On Mon, Jun 1, 2020 at 4:24 PM Alan Grayson  wrote:
>>
>>>
>>>
>>> On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:



 On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson  
 wrote:

>
>
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>
>> I recently wrote an article on the size of the universe and the scope 
>> of reality:
>> https://alwaysasking.com/how-big-is-the-universe/
>>
>> It's first of what I hope will be a series of articles which are 
>> largely inspired by some of the conversations I've enjoyed here. It 
>> covers 
>> many topics including the historic discoveries, the big bang, inflation, 
>> string theory, and mathematical realism.
>>
>> Jason
>>
>
> You claim, 
> "Every very finite sequence recurs an infinite number of times 
> precisely because Pi goes on forever." Can you prove it? AG
>
> "Similarly, should space go on forever then every possible finite 
> arrangement of matter occurs in an infinite number of locations." Even 
> in a finite universe, assuming space is infinitely divisible, this is 
> false 
> IMO. For example, if we live in a finite 4 dimensional hypersphere with 
> only one particle, it can be placed in infinitely different locations and 
> no repeats is plausible.  AG
>
>
>
 You are right, if there are continuous variables of unlimited precision 
 then repeats are infinitely unlikely.

 Where this assumption appears to break down, however, is that quantum 
 mechanics implies an upper bound on the number of distinguishable (in 
 principle) states for a given quantity of mass/energy distributed across a 
 given volume of space. So while you could suppose that two similar-seeming 
 regions are in fact in different

Re: The size of the universe


> On 2 Jun 2020, at 03:07, Alan Grayson  wrote:
> 
> 
> 
> On Monday, June 1, 2020 at 3:58:01 PM UTC-6, Jason wrote:
> Let's say time and space are continuous. Now lets design a stop watch that 
> works as follows:
> 
> 1. Start button: shoots a photon with a wavelength of 300 nanometers down the 
> length of a ruler.
> 2. Stop button: raises the ruler so that the photon hits it at a certain 
> point that we can measure.
> 
> Question: Even if space and time are continuous can this stop watch provide 
> measurements of continuous/unlimited precision?
> 
> Answer: Due to the uncertainty principle, the location the photon cannot be 
> determined to a location finer than the photon's wavelength. Accordingly, 
> even if space/time are continuous, such a stop watch has a discrete 
> time-resolution of (300 nanometers / speed of light ) ~= 10^-15 seconds. So 
> for all practical purposes, there's no difference between this stop-watch 
> 1.1 and 1.2 seconds after pressing 
> "Start". Given this, can we be so sure that reality is continuous?
> 
> David Deutsch has speculated that the appearance of a continuum may be an 
> artifact of living within an infinite ensemble of independently discrete 
> realities. As we see a continuous variable evolve to reach some final state, 
> it may be an increasing fraction of realities evolving to reach that state 
> (with each one discretely changing). This would explain why a photon might 
> seem to have an arbitrary polarization, or an electron some arbitrary 
> fraction of spin, but when measured it only have one of two possible values.
> 
> In summary, I agree with you that a continuous reality rules out exact 
> duplicates. But I would add that quantum mechanics says two regions of space 
> can be so similar to each other that no one, and no experiment, even in 
> theory, could tell the difference between them.
> 
> Jason
> 
> I don't see what measurements of similarity has to do with this issue. Fact 
> is that if space is continuous,

That is not a fact. The fact is that we don’t know, neither with Mechanism, nor 
with physics which has not yet successfully explain how to marry the quantum 
and GR.

With mechanism, the continuum comes from the necessary random oracle of the 
first person posts of view.




> there cannot be any exact repetitions. And not only is position continuous, 
> but so are other variables, which makes the case of uniqueness even stronger. 
> And it doesn't matter whether the universe is finite or infinite in spatial 
> extent. So from my perspective, every universe is unique (provided continuity 
> of spatial extent exists). AG 

Better to not assume a universe, or a god, as those things are what we need to 
explain.

Bruno



> 
> On Mon, Jun 1, 2020 at 4:24 PM Alan Grayson  > wrote:
> 
> 
> On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:
> 
> 
> On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson > wrote:
> 
> 
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
> I recently wrote an article on the size of the universe and the scope of 
> reality:
> https://alwaysasking.com/how-big-is-the-universe/ 
> 
> 
> It's first of what I hope will be a series of articles which are largely 
> inspired by some of the conversations I've enjoyed here. It covers many 
> topics including the historic discoveries, the big bang, inflation, string 
> theory, and mathematical realism.
> 
> Jason
> 
> You claim, 
> "Every very finite sequence recurs an infinite number of times precisely 
> because Pi goes on forever." Can you prove it? AG
> 
> "Similarly, should space go on forever then every possible finite arrangement 
> of matter occurs in an infinite number of locations." Even in a finite 
> universe, assuming space is infinitely divisible, this is false IMO. For 
> example, if we live in a finite 4 dimensional hypersphere with only one 
> particle, it can be placed in infinitely different locations and no repeats 
> is plausible.  AG
> 
> 
> 
> You are right, if there are continuous variables of unlimited precision then 
> repeats are infinitely unlikely.
> 
> Where this assumption appears to break down, however, is that quantum 
> mechanics implies an upper bound on the number of distinguishable (in 
> principle) states for a given quantity of mass/energy distributed across a 
> given volume of space. So while you could suppose that two similar-seeming 
> regions are in fact in different states, there would be no test you could 
> perform to distinguish between the two. (Given the quantum bounds on 
> information storage).
> 
> Jason
> 
> The spectrum for an unbound particle, such as a free electron, is continuous 
> (not discrete). Thus, if the background space is finite OR infinite in 
> extent, there will be no repeats of such a universe since the initial 
> position of any particle, is uncountable.  Although it might not be possible 
> to distinguish two

Re: The size of the universe


> On 2 Jun 2020, at 01:59, Jason Resch  wrote:
> 
> 
> 
> On Monday, June 1, 2020, Bruce Kellett  > wrote:
> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch  > wrote:
> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson  > wrote:
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
> I recently wrote an article on the size of the universe and the scope of 
> reality:
> https://alwaysasking.com/how-big-is-the-universe/ 
> 
> 
> It's first of what I hope will be a series of articles which are largely 
> inspired by some of the conversations I've enjoyed here. It covers many 
> topics including the historic discoveries, the big bang, inflation, string 
> theory, and mathematical realism.
> 
> Jason
> 
> I see you agree with the MUH that there are infinite, identical repeats of 
> any universe.
> 
> To be clear, the MUH is separate theory from the idea of a spatially infinite 
> universe (which is just the standard cosmological model that working 
> cosmologists assume today, that the universe is infinite, homogeneous, and 
> seeded by random quantum fluctuations occurring at all scales during the 
> expansion of the universe).
> 
> 
> Define what you mean by "quantum fluctuations". There are no such things in 
> standard quantum mechanics.
> 
> 
> Variations in the decay of the inflaton field that seeded the variations in 
> density that led to stars and galaxies, and confirmed by observations by COBE 
> and Planck.
>  
>  
>  
> I tend to think the opposite is true; namely, that in an infinite universe, 
> there are no identical repeats; that is, every universe is unique. I've seen 
> that the theory of infinite repeats is often "repeated", but where is the 
> proof? AG 
> 
> The idea is not that the universe itself repeats, only that any finite volume 
> in that space repeats. This can be proved from the pigeon hole principle 
> (which can prove that there is at least one repeat). The proof is as follows.
> 
> Let's consider a volume of the mass and size of the Earth. That is a sphere 
> with a radius of 6,371 km and a mass of 5.8 × 10^24 kg. According to Jacob 
> Bekenstein's bound , the 
> total number of distinct quantum states possible is given by: 2.57 * 10^43 
> bits per (kg * meter).
> 
> For Earth that works out to: 2.57 × 10^43 bits/(kg * meter) * 5.8 × 10^24 kg 
> * 6,371,000 meters = 9.49 × 10^74 bits.
> 
> Given that many bits, it means there are 2 to the power of (9.49 × 10^74), 
> let's say 2^(10^75), possible configurations for an Earth-sized object of 
> similar mass and volume.  It's a large, but finite number. Let's call this 
> number N = 2^(10^75).
> 
> If the universe is infinite, and contains infinite numbers of planets, then 
> there is a finite number of possibilities equal to N. Let's assume the first 
> N such planets are all unique and different from each other. The problem 
> occurs once you get that (N+1)th planet. It can't be unique from all the 
> other N planets which came before it, since there are only N possibilities. 
> Therefore it has to be identical to one of the other N planets.
> 
> 
> That does not preclude the possibility of infinite repeats of just one of the 
> states -- all others being unique. To have repeats of every possible state 
> requires very strong homogeneity assumptions; assumptions that cannot ever be 
> justified.
> 
> True, but I think you would need to add additional (far stronger) assumptions 
> to explain why something could happen exactly once but never again throughout 
> infinite space and those assumptions run counter to standard cosmological 
> ones.


With mechanism, the computations simulating our entire cluster of galaxies, at 
the QED and QCD level (probably lower than our substitution level) occurs (in 
the sigma_1 arithmetical reality, or in the universal dovetailing) in 
infinitely many occurrences.

Indeed the only reason white rabbit disappear is that the normal histories have 
a measure one, in the (mechanist) theory. In nature, that remains to be verify 
again and again …

Bruno 



> 
> Jason
> 
> -- 
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>  
> .

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Re: The size of the universe


> On 1 Jun 2020, at 19:31, Jason Resch  wrote:
> 
> Speaking of large but finite numbers, I think sometimes we forget just how 
> big some finite numbers can be:
> 
> This article really stretched my brain/hurt my head: 
> https://waitbutwhy.com/2014/11/100-grahams-number.html 
>  Numbers can be 
> so big they become scary.

And I have explained how such graham numbers are infinitesimal, compared to 
what logicians can do. I did this to illustrate the transendental power of 
diagonalsiation, on this list, some years ago. I did this to better explain why 
Gödel is right to call the CT thesis a “miracle”. It makes “all computations” 
an explanatively close theory/realm, even close for the most transcendental 
mathematical operation (diagonalisation). It tools a long time for me to 
believe in CT, but I knew since long that if CT is true, physics cannot be the 
fundamental science, and has to be reduced to arithmetic, or to any universal 
machinery.
Arithmetic seen from inside is inconceivably bigger than the physical 
observable universe, in fact it is bigger than the set-theoretical universe … 
yes, it can be scary …

Bruno 



> 
> Jason
> 
> On Sat, May 23, 2020 at 6:37 PM Russell Standish  > wrote:
> On Sat, May 23, 2020 at 12:05:08PM -0700, 'Brent Meeker' via Everything List 
> wrote:
> > 
> > 
> > On 5/23/2020 4:42 AM, Bruno Marchal wrote:
> > > 
> > > Well, those are theorem provable in very weak theories. It is more a
> > > question of grasping the proof than subscribing to a philosophical idea.
> > > That arithmetic executes all programs is a theorem similar to Euclid’s
> > > theorem that there is no biggest prima numbers. It is more a fact, than
> > > an idea which could be debated. I insist on this as I realise this is
> > > less known by the general scientists than 20 years ago. We knew this
> > > implicitly since Gödel 1931, and explicitly since Church, Turing and
> > > Kleene 1936.
> > 
> > Recently you have said that your theory is consistent with finitism, even
> > ultrafinitism.  But the idea that arithemtic exectues all programs certainly
> > requires infinities.
> 
> Only potential infinities, not actual infinities. For the UD (a finite
> object) to execute any given program, one only needs to wait a finite
> amount of time.
> 
> However, I would think that ultrafinitism would change COMP's
> predictions, and in a sense be incompatibe with it. Some programs will
> not exist, because one would need to wait too long for them to be
> executed by the UD. In fact, the choice of reference universal machine
> would be significant in ultrafinitism, IIUC.
> 
> 
> -- 
> 
> 
> Dr Russell StandishPhone 0425 253119 (mobile)
> Principal, High Performance Coders hpco...@hpcoders.com.au 
> 
>   http://www.hpcoders.com.au 
> 
> 
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>  
> .
> 
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Re: The size of the universe


> On 1 Jun 2020, at 15:55, Alan Grayson  wrote:
> 
> 
> 
> On Monday, June 1, 2020 at 7:31:14 AM UTC-6, Alan Grayson wrote:
> 
> 
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
> I recently wrote an article on the size of the universe and the scope of 
> reality:
> https://alwaysasking.com/how-big-is-the-universe/ 
> 
> 
> It's first of what I hope will be a series of articles which are largely 
> inspired by some of the conversations I've enjoyed here. It covers many 
> topics including the historic discoveries, the big bang, inflation, string 
> theory, and mathematical realism.
> 
> Jason
> 
> You claim, 
> "Every very finite sequence recurs an infinite number of times precisely 
> because Pi goes on forever." Can you prove it? AG


I asked Jason, why use PI? It has not been proved fro Pi, but it has been 
proved for some other constructive real numbers.


Bruno



> 
> What you claim above is probably true, but doesn't apply to a universe where 
> space is infinitely divisible since there exists an uncountable set of 
> possible material configerations, as my example below demonstrates. AG
> 
> "Similarly, should space go on forever then every possible finite arrangement 
> of matter occurs in an infinite number of locations." Even in a finite 
> universe, assuming space is infinitely divisible, this is false IMO. For 
> example, if we live in a finite 4 dimensional hypersphere with only one 
> particle, it can be placed in infinitely different locations and no repeats 
> is plausible.  AG
> 
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>  
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Re: The size of the universe


> On 1 Jun 2020, at 13:26, Alan Grayson  wrote:
> 
> 
> 
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
> I recently wrote an article on the size of the universe and the scope of 
> reality:
> https://alwaysasking.com/how-big-is-the-universe/ 
> 
> 
> It's first of what I hope will be a series of articles which are largely 
> inspired by some of the conversations I've enjoyed here. It covers many 
> topics including the historic discoveries, the big bang, inflation, string 
> theory, and mathematical realism.
> 
> Jason
> 
> I see you agree with the MUH that there are infinite, identical repeats of 
> any universe.


With mechanism “universe” does not make sense, but there is an infinity of 
emulations of each computations (in very elementary arithmetic, i.e. PA without 
induction axioms).

Strictly speaking, the digital mechanist theory leads to 0 universes, but many 
histoires/ computations.




> I tend to think the opposite is true; namely, that in an infinite universe, 
> there are no identical repeats; that is, every universe is unique. I've seen 
> that the theory of infinite repeats is often "repeated", but where is the 
> proof? AG 


The many computations in RA is provable in PA, ZF, etc.

Bruno



> 
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>  
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Re: The size of the universe

2020-06-01 Thread Bruce Kellett

On Tue, Jun 2, 2020 at 9:59 AM Jason Resch  wrote:

> On Monday, June 1, 2020, Bruce Kellett  wrote:
>
>> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch  wrote:
>>
>>> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
>>> wrote:
>>>
 On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>
> I recently wrote an article on the size of the universe and the scope
> of reality:
> https://alwaysasking.com/how-big-is-the-universe/
>
> It's first of what I hope will be a series of articles which are
> largely inspired by some of the conversations I've enjoyed here. It covers
> many topics including the historic discoveries, the big bang, inflation,
> string theory, and mathematical realism.
>
> Jason
>

 I see you agree with the MUH that there are infinite, identical repeats
 of any universe.

>>>
>>> To be clear, the MUH is separate theory from the idea of a spatially
>>> infinite universe (which is just the standard cosmological model that
>>> working cosmologists assume today, that the universe is infinite,
>>> homogeneous, and seeded by random quantum fluctuations occurring at all
>>> scales during the expansion of the universe).
>>>
>>
>>
>> Define what you mean by "quantum fluctuations". There are no such things
>> in standard quantum mechanics.
>>
>>
> Variations in the decay of the inflaton field that seeded the variations
> in density that led to stars and galaxies, and confirmed by observations by
> COBE and Planck.
>


That is not how inflation models work.



> I tend to think the opposite is true; namely, that in an infinite
 universe, there are no identical repeats; that is, every universe is
 unique. I've seen that the theory of infinite repeats is often "repeated",
 but where is the proof? AG

>>>
>>> The idea is not that the universe itself repeats, only that any finite
>>> volume in that space repeats. This can be proved from the pigeon hole
>>> principle (which can prove that there is at least one repeat). The proof is
>>> as follows.
>>>
>>> Let's consider a volume of the mass and size of the Earth. That is a
>>> sphere with a radius of 6,371 km and a mass of 5.8 × 10^24 kg. According to 
>>> Jacob
>>> Bekenstein's bound ,
>>> the total number of distinct quantum states possible is given by: 2.57 *
>>> 10^43 bits per (kg * meter).
>>>
>>> For Earth that works out to: 2.57 × 10^43 bits/(kg * meter) * 5.8 ×
>>> 10^24 kg * 6,371,000 meters = 9.49 × 10^74 bits.
>>>
>>> Given that many bits, it means there are 2 to the power of (9.49 ×
>>> 10^74), let's say 2^(10^75), possible configurations for an Earth-sized
>>> object of similar mass and volume.  It's a large, but finite number. Let's
>>> call this number *N = 2^(10^75)*.
>>>
>>> If the universe is infinite, and contains infinite numbers of planets,
>>> then there is a finite number of possibilities equal to *N*. Let's
>>> assume the first *N* such planets are all unique and different from
>>> each other. The problem occurs once you get that *(N+1)*th planet. It
>>> can't be unique from all the other *N* planets which came before it,
>>> since there are only *N* possibilities. Therefore it has to be
>>> identical to one of the other *N* planets.
>>>
>>
>>
>> That does not preclude the possibility of infinite repeats of just one of
>> the states -- all others being unique. To have repeats of every possible
>> state requires very strong homogeneity assumptions; assumptions that cannot
>> ever be justified.
>>
>
> True, but I think you would need to add additional (far stronger)
> assumptions to explain why something could happen exactly once but never
> again throughout infinite space and those assumptions run counter to
> standard cosmological ones.
>

The standard assumption of homogeneity, etc, made in cosmological models
are made for convenience only -- there is no theoretical or practical basis
for those assumptions rather than any other assumptions. We can have
initial conditions of zero measure, after all.

Bruce

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Re: The size of the universe



On Monday, June 1, 2020 at 3:58:01 PM UTC-6, Jason wrote:
>
> Let's say time and space are continuous. Now lets design a stop watch that 
> works as follows:
>
> 1. *Start button:* shoots a photon with a wavelength of 300 nanometers 
> down the length of a ruler.
> 2. *Stop button:* raises the ruler so that the photon hits it at a 
> certain point that we can measure.
>
> Question: Even if space and time are continuous can this stop watch 
> provide measurements of continuous/unlimited precision?
>
> Answer: Due to the uncertainty principle, the location the photon cannot 
> be determined to a location finer than the photon's wavelength. 
> Accordingly, even if space/time are continuous, such a stop watch has a 
> discrete time-resolution of (300 nanometers / speed of light ) ~= 10^-15 
> seconds. So for all practical purposes, there's no difference between this 
> stop-watch 1.1 and 1.2 seconds 
> after pressing "Start". Given this, can we be so sure that reality is 
> continuous?
>
> David Deutsch has speculated that the appearance of a continuum may be an 
> artifact of living within an infinite ensemble of independently discrete 
> realities. As we see a continuous variable evolve to reach some final 
> state, it may be an increasing fraction of realities evolving to reach that 
> state (with each one discretely changing). This would explain why a photon 
> might seem to have an arbitrary polarization, or an electron some arbitrary 
> fraction of spin, but when measured it only have one of two possible values.
>
> In summary, I agree with you that a continuous reality rules out exact 
> duplicates. But I would add that quantum mechanics says two regions of 
> space can be so similar to each other that no one, and no experiment, even 
> in theory, could tell the difference between them.
>
> Jason
>

I don't see what measurements of similarity has to do with this issue. Fact 
is that if space is continuous, there cannot be any exact repetitions. And 
not only is position continuous, but so are other variables, which makes 
the case of uniqueness even stronger. And it doesn't matter whether the 
universe is finite or infinite in spatial extent. So from my perspective, 
every universe is unique (provided continuity of spatial extent exists). AG 

>
> On Mon, Jun 1, 2020 at 4:24 PM Alan Grayson  > wrote:
>
>>
>>
>> On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:
>>>
>>>
>>>
>>> On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson  wrote:
>>>


 On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>
> I recently wrote an article on the size of the universe and the scope 
> of reality:
> https://alwaysasking.com/how-big-is-the-universe/
>
> It's first of what I hope will be a series of articles which are 
> largely inspired by some of the conversations I've enjoyed here. It 
> covers 
> many topics including the historic discoveries, the big bang, inflation, 
> string theory, and mathematical realism.
>
> Jason
>

 You claim, 
 "Every very finite sequence recurs an infinite number of times 
 precisely because Pi goes on forever." Can you prove it? AG

 "Similarly, should space go on forever then every possible finite 
 arrangement of matter occurs in an infinite number of locations." Even 
 in a finite universe, assuming space is infinitely divisible, this is 
 false 
 IMO. For example, if we live in a finite 4 dimensional hypersphere with 
 only one particle, it can be placed in infinitely different locations and 
 no repeats is plausible.  AG



>>> You are right, if there are continuous variables of unlimited precision 
>>> then repeats are infinitely unlikely.
>>>
>>> Where this assumption appears to break down, however, is that quantum 
>>> mechanics implies an upper bound on the number of distinguishable (in 
>>> principle) states for a given quantity of mass/energy distributed across a 
>>> given volume of space. So while you could suppose that two similar-seeming 
>>> regions are in fact in different states, there would be no test you could 
>>> perform to distinguish between the two. (Given the quantum bounds on 
>>> information storage).
>>>
>>> Jason
>>>
>>
>> The spectrum for an unbound particle, such as a free electron, is 
>> continuous (not discrete). Thus, if the background space is finite OR 
>> infinite in extent, there will be no repeats of such a universe since the 
>> initial position of any particle, is uncountable.  Although it might not be 
>> possible to distinguish two distinct initial states by measurement, I don't 
>> see how their existence can be denied. AG 
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "Everything List" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to everyth...@googlegroups.com .
>> To view this

Re: The size of the universe

On Monday, June 1, 2020, Bruce Kellett  wrote:

> On Tue, Jun 2, 2020 at 5:39 AM Jason Resch  wrote:
>
>> On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson 
>> wrote:
>>
>>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:

 I recently wrote an article on the size of the universe and the scope
 of reality:
 https://alwaysasking.com/how-big-is-the-universe/

 It's first of what I hope will be a series of articles which are
 largely inspired by some of the conversations I've enjoyed here. It covers
 many topics including the historic discoveries, the big bang, inflation,
 string theory, and mathematical realism.

 Jason

>>>
>>> I see you agree with the MUH that there are infinite, identical repeats
>>> of any universe.
>>>
>>
>> To be clear, the MUH is separate theory from the idea of a spatially
>> infinite universe (which is just the standard cosmological model that
>> working cosmologists assume today, that the universe is infinite,
>> homogeneous, and seeded by random quantum fluctuations occurring at all
>> scales during the expansion of the universe).
>>
>
>
> Define what you mean by "quantum fluctuations". There are no such things
> in standard quantum mechanics.
>
>
Variations in the decay of the inflaton field that seeded the variations in
density that led to stars and galaxies, and confirmed by observations by
COBE and Planck.


>
>
>>
>>
>>> I tend to think the opposite is true; namely, that in an infinite
>>> universe, there are no identical repeats; that is, every universe is
>>> unique. I've seen that the theory of infinite repeats is often "repeated",
>>> but where is the proof? AG
>>>
>>
>> The idea is not that the universe itself repeats, only that any finite
>> volume in that space repeats. This can be proved from the pigeon hole
>> principle (which can prove that there is at least one repeat). The proof is
>> as follows.
>>
>> Let's consider a volume of the mass and size of the Earth. That is a
>> sphere with a radius of 6,371 km and a mass of 5.8 × 10^24 kg. According to 
>> Jacob
>> Bekenstein's bound , the
>> total number of distinct quantum states possible is given by: 2.57 * 10^43
>> bits per (kg * meter).
>>
>> For Earth that works out to: 2.57 × 10^43 bits/(kg * meter) * 5.8 × 10^24
>> kg * 6,371,000 meters = 9.49 × 10^74 bits.
>>
>> Given that many bits, it means there are 2 to the power of (9.49 ×
>> 10^74), let's say 2^(10^75), possible configurations for an Earth-sized
>> object of similar mass and volume.  It's a large, but finite number. Let's
>> call this number *N = 2^(10^75)*.
>>
>> If the universe is infinite, and contains infinite numbers of planets,
>> then there is a finite number of possibilities equal to *N*. Let's
>> assume the first *N* such planets are all unique and different from each
>> other. The problem occurs once you get that *(N+1)*th planet. It can't
>> be unique from all the other *N* planets which came before it, since
>> there are only *N* possibilities. Therefore it has to be identical to
>> one of the other *N* planets.
>>
>
>
> That does not preclude the possibility of infinite repeats of just one of
> the states -- all others being unique. To have repeats of every possible
> state requires very strong homogeneity assumptions; assumptions that cannot
> ever be justified.
>

True, but I think you would need to add additional (far stronger)
assumptions to explain why something could happen exactly once but never
again throughout infinite space and those assumptions run counter to
standard cosmological ones.

Jason

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Re: The size of the universe

Let's say time and space are continuous. Now lets design a stop watch that
works as follows:

1. *Start button:* shoots a photon with a wavelength of 300 nanometers down
the length of a ruler.
2. *Stop button:* raises the ruler so that the photon hits it at a certain
point that we can measure.

Question: Even if space and time are continuous can this stop watch provide
measurements of continuous/unlimited precision?

Answer: Due to the uncertainty principle, the location the photon cannot be
determined to a location finer than the photon's wavelength. Accordingly,
even if space/time are continuous, such a stop watch has a discrete
time-resolution of (300 nanometers / speed of light ) ~= 10^-15 seconds. So
for all practical purposes, there's no difference between this stop-watch
1.1 and 1.2 seconds after pressing
"Start". Given this, can we be so sure that reality is continuous?

David Deutsch has speculated that the appearance of a continuum may be an
artifact of living within an infinite ensemble of independently discrete
realities. As we see a continuous variable evolve to reach some final
state, it may be an increasing fraction of realities evolving to reach that
state (with each one discretely changing). This would explain why a photon
might seem to have an arbitrary polarization, or an electron some arbitrary
fraction of spin, but when measured it only have one of two possible values.

In summary, I agree with you that a continuous reality rules out exact
duplicates. But I would add that quantum mechanics says two regions of
space can be so similar to each other that no one, and no experiment, even
in theory, could tell the difference between them.

Jason

On Mon, Jun 1, 2020 at 4:24 PM Alan Grayson  wrote:

>
>
> On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:
>>
>>
>>
>> On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson  wrote:
>>
>>>
>>>
>>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:

 I recently wrote an article on the size of the universe and the scope
 of reality:
 https://alwaysasking.com/how-big-is-the-universe/

 It's first of what I hope will be a series of articles which are
 largely inspired by some of the conversations I've enjoyed here. It covers
 many topics including the historic discoveries, the big bang, inflation,
 string theory, and mathematical realism.

 Jason

>>>
>>> You claim,
>>> "Every very finite sequence recurs an infinite number of times precisely
>>> because Pi goes on forever." Can you prove it? AG
>>>
>>> "Similarly, should space go on forever then every possible finite
>>> arrangement of matter occurs in an infinite number of locations." Even
>>> in a finite universe, assuming space is infinitely divisible, this is false
>>> IMO. For example, if we live in a finite 4 dimensional hypersphere with
>>> only one particle, it can be placed in infinitely different locations and
>>> no repeats is plausible.  AG
>>>
>>>
>>>
>> You are right, if there are continuous variables of unlimited precision
>> then repeats are infinitely unlikely.
>>
>> Where this assumption appears to break down, however, is that quantum
>> mechanics implies an upper bound on the number of distinguishable (in
>> principle) states for a given quantity of mass/energy distributed across a
>> given volume of space. So while you could suppose that two similar-seeming
>> regions are in fact in different states, there would be no test you could
>> perform to distinguish between the two. (Given the quantum bounds on
>> information storage).
>>
>> Jason
>>
>
> The spectrum for an unbound particle, such as a free electron, is
> continuous (not discrete). Thus, if the background space is finite OR
> infinite in extent, there will be no repeats of such a universe since the
> initial position of any particle, is uncountable.  Although it might not be
> possible to distinguish two distinct initial states by measurement, I don't
> see how their existence can be denied. AG
>
> --
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> "Everything List" group.
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> email to everything-list+unsubscr...@googlegroups.com.
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> 
> .
>

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Re: The size of the universe



On Monday, June 1, 2020 at 1:43:09 PM UTC-6, Jason wrote:
>
>
>
> On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson  > wrote:
>
>>
>>
>> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>>
>>> I recently wrote an article on the size of the universe and the scope of 
>>> reality:
>>> https://alwaysasking.com/how-big-is-the-universe/
>>>
>>> It's first of what I hope will be a series of articles which are 
>>> largely inspired by some of the conversations I've enjoyed here. It covers 
>>> many topics including the historic discoveries, the big bang, inflation, 
>>> string theory, and mathematical realism.
>>>
>>> Jason
>>>
>>
>> You claim, 
>> "Every very finite sequence recurs an infinite number of times precisely 
>> because Pi goes on forever." Can you prove it? AG
>>
>> "Similarly, should space go on forever then every possible finite 
>> arrangement of matter occurs in an infinite number of locations." Even 
>> in a finite universe, assuming space is infinitely divisible, this is false 
>> IMO. For example, if we live in a finite 4 dimensional hypersphere with 
>> only one particle, it can be placed in infinitely different locations and 
>> no repeats is plausible.  AG
>>
>>
>>
> You are right, if there are continuous variables of unlimited precision 
> then repeats are infinitely unlikely.
>
> Where this assumption appears to break down, however, is that quantum 
> mechanics implies an upper bound on the number of distinguishable (in 
> principle) states for a given quantity of mass/energy distributed across a 
> given volume of space. So while you could suppose that two similar-seeming 
> regions are in fact in different states, there would be no test you could 
> perform to distinguish between the two. (Given the quantum bounds on 
> information storage).
>
> Jason
>

The spectrum for an unbound particle, such as a free electron, is 
continuous (not discrete). Thus, if the background space is finite OR 
infinite in extent, there will be no repeats of such a universe since the 
initial position of any particle, is uncountable.  Although it might not be 
possible to distinguish two distinct initial states by measurement, I don't 
see how their existence can be denied. AG 

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Re: The size of the universe

On Mon, Jun 1, 2020 at 8:31 AM Alan Grayson  wrote:

>
>
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>
>> I recently wrote an article on the size of the universe and the scope of
>> reality:
>> https://alwaysasking.com/how-big-is-the-universe/
>>
>> It's first of what I hope will be a series of articles which are
>> largely inspired by some of the conversations I've enjoyed here. It covers
>> many topics including the historic discoveries, the big bang, inflation,
>> string theory, and mathematical realism.
>>
>> Jason
>>
>
> You claim,
> "Every very finite sequence recurs an infinite number of times precisely
> because Pi goes on forever." Can you prove it? AG
>
> "Similarly, should space go on forever then every possible finite
> arrangement of matter occurs in an infinite number of locations." Even in
> a finite universe, assuming space is infinitely divisible, this is false
> IMO. For example, if we live in a finite 4 dimensional hypersphere with
> only one particle, it can be placed in infinitely different locations and
> no repeats is plausible.  AG
>
>
>
You are right, if there are continuous variables of unlimited precision
then repeats are infinitely unlikely.

Where this assumption appears to break down, however, is that quantum
mechanics implies an upper bound on the number of distinguishable (in
principle) states for a given quantity of mass/energy distributed across a
given volume of space. So while you could suppose that two similar-seeming
regions are in fact in different states, there would be no test you could
perform to distinguish between the two. (Given the quantum bounds on
information storage).

Jason

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Re: The size of the universe

On Mon, Jun 1, 2020 at 6:26 AM Alan Grayson  wrote:

>
>
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>
>> I recently wrote an article on the size of the universe and the scope of
>> reality:
>> https://alwaysasking.com/how-big-is-the-universe/
>>
>> It's first of what I hope will be a series of articles which are
>> largely inspired by some of the conversations I've enjoyed here. It covers
>> many topics including the historic discoveries, the big bang, inflation,
>> string theory, and mathematical realism.
>>
>> Jason
>>
>
> I see you agree with the MUH that there are infinite, identical repeats of
> any universe.
>

To be clear, the MUH is separate theory from the idea of a spatially
infinite universe (which is just the standard cosmological model that
working cosmologists assume today, that the universe is infinite,
homogeneous, and seeded by random quantum fluctuations occurring at all
scales during the expansion of the universe).

> I tend to think the opposite is true; namely, that in an infinite
> universe, there are no identical repeats; that is, every universe is
> unique. I've seen that the theory of infinite repeats is often "repeated",
> but where is the proof? AG
>

The idea is not that the universe itself repeats, only that any finite
volume in that space repeats. This can be proved from the pigeon hole
principle (which can prove that there is at least one repeat). The proof is
as follows.

Let's consider a volume of the mass and size of the Earth. That is a sphere
with a radius of 6,371 km and a mass of 5.8 × 10^24 kg. According to Jacob
Bekenstein's bound , the
total number of distinct quantum states possible is given by: 2.57 * 10^43
bits per (kg * meter).

For Earth that works out to: 2.57 × 10^43 bits/(kg * meter) * 5.8 × 10^24
kg * 6,371,000 meters = 9.49 × 10^74 bits.

Given that many bits, it means there are 2 to the power of (9.49 × 10^74),
let's say 2^(10^75), possible configurations for an Earth-sized object of
similar mass and volume.  It's a large, but finite number. Let's call this
number *N = 2^(10^75)*.

If the universe is infinite, and contains infinite numbers of planets, then
there is a finite number of possibilities equal to *N*. Let's assume the
first *N* such planets are all unique and different from each other. The
problem occurs once you get that *(N+1)*th planet. It can't be unique from
all the other *N* planets which came before it, since there are only *N*
possibilities. Therefore it has to be identical to one of the other *N*
planets.

It's like sequences of flipping coins. There are only 16 possible results
(in terms of heads/tails) from flipping 4 coins. Once you are on your 17th
set of flipping the coins, you are  guaranteed to have a repeated sequence
that is identical to one of the 16 other times you flipped 4 coins.

Jason

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Re: The size of the universe

Speaking of large but finite numbers, I think sometimes we forget just how
big some finite numbers can be:

This article really stretched my brain/hurt my head:
https://waitbutwhy.com/2014/11/100-grahams-number.html Numbers can be
so big they become scary.

Jason

On Sat, May 23, 2020 at 6:37 PM Russell Standish 
wrote:

> On Sat, May 23, 2020 at 12:05:08PM -0700, 'Brent Meeker' via Everything
> List wrote:
> >
> >
> > On 5/23/2020 4:42 AM, Bruno Marchal wrote:
> > >
> > > Well, those are theorem provable in very weak theories. It is more a
> > > question of grasping the proof than subscribing to a philosophical
> idea.
> > > That arithmetic executes all programs is a theorem similar to Euclid’s
> > > theorem that there is no biggest prima numbers. It is more a fact, than
> > > an idea which could be debated. I insist on this as I realise this is
> > > less known by the general scientists than 20 years ago. We knew this
> > > implicitly since Gödel 1931, and explicitly since Church, Turing and
> > > Kleene 1936.
> >
> > Recently you have said that your theory is consistent with finitism, even
> > ultrafinitism.  But the idea that arithemtic exectues all programs
> certainly
> > requires infinities.
>
> Only potential infinities, not actual infinities. For the UD (a finite
> object) to execute any given program, one only needs to wait a finite
> amount of time.
>
> However, I would think that ultrafinitism would change COMP's
> predictions, and in a sense be incompatibe with it. Some programs will
> not exist, because one would need to wait too long for them to be
> executed by the UD. In fact, the choice of reference universal machine
> would be significant in ultrafinitism, IIUC.
>
>
> --
>
>
> 
> Dr Russell StandishPhone 0425 253119 (mobile)
> Principal, High Performance Coders hpco...@hpcoders.com.au
>   http://www.hpcoders.com.au
>
> 
>
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> .
>

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Re: The size of the universe



On Monday, June 1, 2020 at 7:31:14 AM UTC-6, Alan Grayson wrote:
>
>
>
> On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>>
>> I recently wrote an article on the size of the universe and the scope of 
>> reality:
>> https://alwaysasking.com/how-big-is-the-universe/
>>
>> It's first of what I hope will be a series of articles which are 
>> largely inspired by some of the conversations I've enjoyed here. It covers 
>> many topics including the historic discoveries, the big bang, inflation, 
>> string theory, and mathematical realism.
>>
>> Jason
>>
>
> You claim, 
> "Every very finite sequence recurs an infinite number of times precisely 
> because Pi goes on forever." Can you prove it? AG
>

What you claim above is probably true, but doesn't apply to a universe 
where space is infinitely divisible since there exists an uncountable set 
of possible material configerations, as my example below demonstrates. AG

"Similarly, should space go on forever then every possible finite 
> arrangement of matter occurs in an infinite number of locations." Even in 
> a finite universe, assuming space is infinitely divisible, this is false 
> IMO. For example, if we live in a finite 4 dimensional hypersphere with 
> only one particle, it can be placed in infinitely different locations and 
> no repeats is plausible.  AG
>

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Re: The size of the universe

On Monday, May 18, 2020 at 9:20:36 PM UTC-6, Jason wrote:
>
> I recently wrote an article on the size of the universe and the scope of 
> reality:
> https://alwaysasking.com/how-big-is-the-universe/
>
> It's first of what I hope will be a series of articles which are 
> largely inspired by some of the conversations I've enjoyed here. It covers 
> many topics including the historic discoveries, the big bang, inflation, 
> string theory, and mathematical realism.
>
> Jason
>

You claim, 
"Every very finite sequence recurs an infinite number of times precisely 
because Pi goes on forever." Can you prove it? AG

"Similarly, should space go on forever then every possible finite 
arrangement of matter occurs in an infinite number of locations." Even in a 
finite universe, assuming space is infinitely divisible, this is false IMO. 
For example, if we live in a finite 4 dimensional hypersphere with only one 
particle, it can be placed in infinitely different locations and no repeats 
is plausible.  AG

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Re: The size of the universe