Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 12:35 pm, Brent Meeker wrote:

On 12/11/2017 4:44 PM, smitra wrote:

On 11-12-2017 23:15, Bruce Kellett wrote:

...

Rubbish. The central point of contention on this thread is whether a
coin toss can be regarded as a classical event, with probabilities
given by ignorance of the initial conditions, or as a quantum event
with probabilities given by purely quantum uncertainties.

This is a straightforward question of physics, and has nothing to do
with metaphysics. As usual, you introduce the term 'metaphysics'
merely to obfuscate, because you have no intelligent response to the
clear physics of the situation.



That the probabilities are given by classical physics does not imply 
that there is no branching due to the coin toss.


The trouble with that view is it implies that there is branching due 
to everything, since even the most "classical" event has a small 
probability of occurring otherwise.


I think that that is what Saibal believes. And the classical probability 
for something else happening doesn't even have to be small -- it is 
50/50 for the coin toss, after all. Just because something else might 
happen, it does not follow that there is branching as in unitary evolution.


Bruce

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 12/11/2017 6:02 PM, Bruce Kellett wrote:

On 12/12/2017 12:29 pm, agrayson2...@gmail.com wrote:

On Tuesday, December 12, 2017 at 1:25:11 AM UTC, Bruce wrote:

On 12/12/2017 12:18 pm, agrays...@gmail.com  wrote:

On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote:

On 12/12/2017 11:44 am, smitra wrote:
> On 11-12-2017 23:15, Bruce Kellett wrote:
>> On 12/12/2017 1:12 am, Bruno Marchal wrote:
>>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote:
 On 11/12/2017 2:19 am, Bruno Marchal wrote:
> On 09 Dec 2017, at 00:03, Bruce Kellett wrote:
>> On 9/12/2017 4:21 am, Bruno Marchal wrote:
>>> Similarly, a shroedinger car, once alive + dead,
will never
>>> become a pure alive, or dead cat. It will only seems
so for
>>> anyone looking at the cat, in the {alive, dead}
base/apparatus.
>>> Superposition never disappear, and a coin moree or
less with a
>>> precise position, is always a superposition of a
coin with more
>>> or less precise momenta. The relation is given by
the Fourier
>>> transforms, which gives the relative accessible
states/worlds.
>>
>> I pointed out that for a macroscopic object such as a
coin, the
>> uncertainty relations give uncertainties in positions
and/or
>> momentum far below any level of possible detection.
>
> Of possible practical detection. That is good FAPP,
but irrelevant
> for theoretical consideration.

 This is a purely rhetorical objection, Bruno. And when
you trot
 this out, as you do regularly, I know that your purpose
is to
 obfuscate, and hide the fact that you have no rational
argument to
 offer.
>>>
>>> You confuse physics and metaphysics. The difference is not
>>> rhetorical, but fundamental in this thread.
>>
>> Rubbish. The central point of contention on this thread
is whether a
>> coin toss can be regarded as a classical event, with
probabilities
>> given by ignorance of the initial conditions, or as a
quantum event
>> with probabilities given by purely quantum uncertainties.
>>
>> This is a straightforward question of physics, and has
nothing to do
>> with metaphysics. As usual, you introduce the term
'metaphysics'
>> merely to obfuscate, because you have no intelligent
response to the
>> clear physics of the situation.
>>
>
> That the probabilities are given by classical physics does
not imply
> that there is no branching due to the coin toss.

It does, because there is no superposition of head/tails -- no
possibility of interference between heads and tails.

Bruce


Why no inference? Is it because the coin isn't an isolated
system, which IIUC is a necessary condition for interference? AG


It is not a coherent superposition. Do an experiment and see if
there is interference. Is Schrödinger's cat dear or alive?

Bruce


What are the necessary conditions for interference?


Coherent superposition.


For the cat, I have no clue how to do that experiment. Do you? AG


No. Nor for the coin toss.


All you have to do is scale up the Cheshire cat experiment and show that 
the angular momentum of the coin can take a different path through 
spacetime than the coin itself.   :-)   A Nobel prize awaits.


Brent

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 12:29 pm, agrayson2...@gmail.com wrote:

On Tuesday, December 12, 2017 at 1:25:11 AM UTC, Bruce wrote:

On 12/12/2017 12:18 pm, agrays...@gmail.com  wrote:

On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote:

On 12/12/2017 11:44 am, smitra wrote:
> On 11-12-2017 23:15, Bruce Kellett wrote:
>> On 12/12/2017 1:12 am, Bruno Marchal wrote:
>>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote:
 On 11/12/2017 2:19 am, Bruno Marchal wrote:
> On 09 Dec 2017, at 00:03, Bruce Kellett wrote:
>> On 9/12/2017 4:21 am, Bruno Marchal wrote:
>>> Similarly, a shroedinger car, once alive + dead, will
never
>>> become a pure alive, or dead cat. It will only seems
so for
>>> anyone looking at the cat, in the {alive, dead}
base/apparatus.
>>> Superposition never disappear, and a coin moree or
less with a
>>> precise position, is always a superposition of a coin
with more
>>> or less precise momenta. The relation is given by the
Fourier
>>> transforms, which gives the relative accessible
states/worlds.
>>
>> I pointed out that for a macroscopic object such as a
coin, the
>> uncertainty relations give uncertainties in positions
and/or
>> momentum far below any level of possible detection.
>
> Of possible practical detection. That is good FAPP, but
irrelevant
> for theoretical consideration.

 This is a purely rhetorical objection, Bruno. And when
you trot
 this out, as you do regularly, I know that your purpose
is to
 obfuscate, and hide the fact that you have no rational
argument to
 offer.
>>>
>>> You confuse physics and metaphysics. The difference is not
>>> rhetorical, but fundamental in this thread.
>>
>> Rubbish. The central point of contention on this thread is
whether a
>> coin toss can be regarded as a classical event, with
probabilities
>> given by ignorance of the initial conditions, or as a
quantum event
>> with probabilities given by purely quantum uncertainties.
>>
>> This is a straightforward question of physics, and has
nothing to do
>> with metaphysics. As usual, you introduce the term
'metaphysics'
>> merely to obfuscate, because you have no intelligent
response to the
>> clear physics of the situation.
>>
>
> That the probabilities are given by classical physics does
not imply
> that there is no branching due to the coin toss.

It does, because there is no superposition of head/tails -- no
possibility of interference between heads and tails.

Bruce


Why no inference? Is it because the coin isn't an isolated
system, which IIUC is a necessary condition for interference? AG


It is not a coherent superposition. Do an experiment and see if
there is interference. Is Schrödinger's cat dear or alive?

Bruce


What are the necessary conditions for interference?


Coherent superposition.


For the cat, I have no clue how to do that experiment. Do you? AG


No. Nor for the coin toss.

Bruce

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Re: Consistency of Postulates of QM

[agrayson2000]

On Tuesday, December 12, 2017 at 1:29:17 AM UTC, agrays...@gmail.com wrote:
>
>
>
> On Tuesday, December 12, 2017 at 1:25:11 AM UTC, Bruce wrote:
>>
>> On 12/12/2017 12:18 pm, agrays...@gmail.com wrote:
>>
>> On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote: 
>>>
>>> On 12/12/2017 11:44 am, smitra wrote: 
>>> > On 11-12-2017 23:15, Bruce Kellett wrote: 
>>> >> On 12/12/2017 1:12 am, Bruno Marchal wrote: 
>>> >>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote: 
>>>  On 11/12/2017 2:19 am, Bruno Marchal wrote: 
>>> > On 09 Dec 2017, at 00:03, Bruce Kellett wrote: 
>>> >> On 9/12/2017 4:21 am, Bruno Marchal wrote: 
>>> >>> Similarly, a shroedinger car, once alive + dead, will never 
>>> >>> become a pure alive, or dead cat. It will only seems so for 
>>> >>> anyone looking at the cat, in the {alive, dead} base/apparatus. 
>>> >>> Superposition never disappear, and a coin moree or less with a 
>>> >>> precise position, is always a superposition of a coin with more 
>>> >>> or less precise momenta. The relation is given by the Fourier 
>>> >>> transforms, which gives the relative accessible states/worlds. 
>>> >> 
>>> >> I pointed out that for a macroscopic object such as a coin, the 
>>> >> uncertainty relations give uncertainties in positions and/or 
>>> >> momentum far below any level of possible detection. 
>>> > 
>>> > Of possible practical detection. That is good FAPP, but irrelevant 
>>> > for theoretical consideration. 
>>>  
>>>  This is a purely rhetorical objection, Bruno. And when you trot 
>>>  this out, as you do regularly, I know that your purpose is to 
>>>  obfuscate, and hide the fact that you have no rational argument to 
>>>  offer. 
>>> >>> 
>>> >>> You confuse physics and metaphysics. The difference is not 
>>> >>> rhetorical, but fundamental in this thread. 
>>> >> 
>>> >> Rubbish. The central point of contention on this thread is whether a 
>>> >> coin toss can be regarded as a classical event, with probabilities 
>>> >> given by ignorance of the initial conditions, or as a quantum event 
>>> >> with probabilities given by purely quantum uncertainties. 
>>> >> 
>>> >> This is a straightforward question of physics, and has nothing to do 
>>> >> with metaphysics. As usual, you introduce the term 'metaphysics' 
>>> >> merely to obfuscate, because you have no intelligent response to the 
>>> >> clear physics of the situation. 
>>> >> 
>>> > 
>>> > That the probabilities are given by classical physics does not imply 
>>> > that there is no branching due to the coin toss. 
>>>
>>> It does, because there is no superposition of head/tails -- no 
>>> possibility of interference between heads and tails. 
>>>
>>> Bruce 
>>>
>>
>> Why no inference? Is it because the coin isn't an isolated system, which 
>> IIUC is a necessary condition for interference? AG 
>>
>>
>> It is not a coherent superposition. Do an experiment and see if there is 
>> interference. Is Schrödinger's cat dear or alive?
>>
>> Bruce
>>
>
>  

> What are the necessary conditions for interference? For the cat, I have no 
> clue how to do that experiment. Do you? AG
>

IMO, the necessary conditions for quantum interference are coherence AND 
isolation. AG 

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 12/11/2017 4:54 PM, smitra wrote:

As I have said before, the biggest challenge for quantum physics is to
explain the emergence of the classical world from the quantum
substrate, so that classical calculations actually get the correct
answers in those classical situations. If you do not believe that
these classical calculations are correct, then I advise you not ever
to drive your car on a busy road.



There is no way a Hilbert space can become a classical configuration 
space. If one sticks to a  falsified theory (in the domain where you 
can hide the shortcomings under the carpet) and cast doubt on a theory 
that has withstood rigorous experimental tests, then it's likely that 
attitude that's the cause of most problems. 


That's what I mean by logic chopping.  Everything is quantum therefore 
every uncertainty is quantum uncertainty...therefore all insurance 
companies should be studying Hilbert space.  This overlooks the fact 
that the classical world is far better empirically supported than the 
quantum world and there is consistency between quantum mechanics and our 
theory of spacetime. It is like Bruno's argument that starts with the 
assumption that his theory is correct in order to prove that fundamental 
physics (whatever that is) is wrong.


Brent

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 12/11/2017 4:44 PM, smitra wrote:

On 11-12-2017 23:15, Bruce Kellett wrote:

...

Rubbish. The central point of contention on this thread is whether a
coin toss can be regarded as a classical event, with probabilities
given by ignorance of the initial conditions, or as a quantum event
with probabilities given by purely quantum uncertainties.

This is a straightforward question of physics, and has nothing to do
with metaphysics. As usual, you introduce the term 'metaphysics'
merely to obfuscate, because you have no intelligent response to the
clear physics of the situation.



That the probabilities are given by classical physics does not imply 
that there is no branching due to the coin toss.


The trouble with that view is it implies that there is branching due to 
everything, since even the most "classical" event has a small 
probability of occurring otherwise.


Brent

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Re: Consistency of Postulates of QM

[agrayson2000]

On Tuesday, December 12, 2017 at 1:25:11 AM UTC, Bruce wrote:
>
> On 12/12/2017 12:18 pm, agrays...@gmail.com  wrote:
>
> On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote: 
>>
>> On 12/12/2017 11:44 am, smitra wrote: 
>> > On 11-12-2017 23:15, Bruce Kellett wrote: 
>> >> On 12/12/2017 1:12 am, Bruno Marchal wrote: 
>> >>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote: 
>>  On 11/12/2017 2:19 am, Bruno Marchal wrote: 
>> > On 09 Dec 2017, at 00:03, Bruce Kellett wrote: 
>> >> On 9/12/2017 4:21 am, Bruno Marchal wrote: 
>> >>> Similarly, a shroedinger car, once alive + dead, will never 
>> >>> become a pure alive, or dead cat. It will only seems so for 
>> >>> anyone looking at the cat, in the {alive, dead} base/apparatus. 
>> >>> Superposition never disappear, and a coin moree or less with a 
>> >>> precise position, is always a superposition of a coin with more 
>> >>> or less precise momenta. The relation is given by the Fourier 
>> >>> transforms, which gives the relative accessible states/worlds. 
>> >> 
>> >> I pointed out that for a macroscopic object such as a coin, the 
>> >> uncertainty relations give uncertainties in positions and/or 
>> >> momentum far below any level of possible detection. 
>> > 
>> > Of possible practical detection. That is good FAPP, but irrelevant 
>> > for theoretical consideration. 
>>  
>>  This is a purely rhetorical objection, Bruno. And when you trot 
>>  this out, as you do regularly, I know that your purpose is to 
>>  obfuscate, and hide the fact that you have no rational argument to 
>>  offer. 
>> >>> 
>> >>> You confuse physics and metaphysics. The difference is not 
>> >>> rhetorical, but fundamental in this thread. 
>> >> 
>> >> Rubbish. The central point of contention on this thread is whether a 
>> >> coin toss can be regarded as a classical event, with probabilities 
>> >> given by ignorance of the initial conditions, or as a quantum event 
>> >> with probabilities given by purely quantum uncertainties. 
>> >> 
>> >> This is a straightforward question of physics, and has nothing to do 
>> >> with metaphysics. As usual, you introduce the term 'metaphysics' 
>> >> merely to obfuscate, because you have no intelligent response to the 
>> >> clear physics of the situation. 
>> >> 
>> > 
>> > That the probabilities are given by classical physics does not imply 
>> > that there is no branching due to the coin toss. 
>>
>> It does, because there is no superposition of head/tails -- no 
>> possibility of interference between heads and tails. 
>>
>> Bruce 
>>
>
> Why no inference? Is it because the coin isn't an isolated system, which 
> IIUC is a necessary condition for interference? AG 
>
>
> It is not a coherent superposition. Do an experiment and see if there is 
> interference. Is Schrödinger's cat dear or alive?
>
> Bruce
>

What are the necessary conditions for interference? For the cat, I have no 
clue how to do that experiment. Do you? AG

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 11:54 am, smitra wrote:

On 11-12-2017 23:24, Bruce Kellett wrote:


As I have said before, the biggest challenge for quantum physics is to
explain the emergence of the classical world from the quantum
substrate, so that classical calculations actually get the correct
answers in those classical situations. If you do not believe that
these classical calculations are correct, then I advise you not ever
to drive your car on a busy road.


There is no way a Hilbert space can become a classical configuration 
space. If one sticks to a  falsified theory (in the domain where you 
can hide the shortcomings under the carpet) and cast doubt on a theory 
that has withstood rigorous experimental tests, then it's likely that 
attitude that's the cause of most problems.


I think you have to take account of decoherence, and the reduction of 
the density matrix to diagonal form FAPP. The diagonal density matrix 
corresponds to normal classical probabilities and disjoint Everettian 
worlds. After all, classical physics has withstood the most rigorous 
experimental tests in its proper domain. Quantum theory does nothing to 
undermine these results.


Bruce

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 12:18 pm, agrayson2...@gmail.com wrote:

On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote:

On 12/12/2017 11:44 am, smitra wrote:
> On 11-12-2017 23:15, Bruce Kellett wrote:
>> On 12/12/2017 1:12 am, Bruno Marchal wrote:
>>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote:
 On 11/12/2017 2:19 am, Bruno Marchal wrote:
> On 09 Dec 2017, at 00:03, Bruce Kellett wrote:
>> On 9/12/2017 4:21 am, Bruno Marchal wrote:
>>> Similarly, a shroedinger car, once alive + dead, will never
>>> become a pure alive, or dead cat. It will only seems so for
>>> anyone looking at the cat, in the {alive, dead}
base/apparatus.
>>> Superposition never disappear, and a coin moree or less
with a
>>> precise position, is always a superposition of a coin with
more
>>> or less precise momenta. The relation is given by the Fourier
>>> transforms, which gives the relative accessible
states/worlds.
>>
>> I pointed out that for a macroscopic object such as a coin,
the
>> uncertainty relations give uncertainties in positions and/or
>> momentum far below any level of possible detection.
>
> Of possible practical detection. That is good FAPP, but
irrelevant
> for theoretical consideration.

 This is a purely rhetorical objection, Bruno. And when you trot
 this out, as you do regularly, I know that your purpose is to
 obfuscate, and hide the fact that you have no rational
argument to
 offer.
>>>
>>> You confuse physics and metaphysics. The difference is not
>>> rhetorical, but fundamental in this thread.
>>
>> Rubbish. The central point of contention on this thread is
whether a
>> coin toss can be regarded as a classical event, with probabilities
>> given by ignorance of the initial conditions, or as a quantum
event
>> with probabilities given by purely quantum uncertainties.
>>
>> This is a straightforward question of physics, and has nothing
to do
>> with metaphysics. As usual, you introduce the term 'metaphysics'
>> merely to obfuscate, because you have no intelligent response
to the
>> clear physics of the situation.
>>
>
> That the probabilities are given by classical physics does not
imply
> that there is no branching due to the coin toss.

It does, because there is no superposition of head/tails -- no
possibility of interference between heads and tails.

Bruce


Why no inference? Is it because the coin isn't an isolated system, 
which IIUC is a necessary condition for interference? AG


It is not a coherent superposition. Do an experiment and see if there is 
interference. Is Schrödinger's cat dear or alive?


Bruce

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Re: Equivalence Principle and Einstein Field Equations

[Russell Standish]

On Mon, Dec 11, 2017 at 12:15:58PM -0800, agrayson2...@gmail.com wrote:
> 
> *IIUC, you're saying that tensors transform covariantly, that is, 
> independent of coordinate system, but you haven't addressed my question why 
> Einstein would think accelerating frames are equivalent, or why a theory of 
> gravity could be, or must be covariant. BTW, is it correct to say that 
> "covariance" is a synonym for "Lorentz invariant"? TIA, AG*

All physical theories must be covariant. It is nonsense for physical
law to depend on one's chosen coordinate system.

Lorentz invariance is just one form of covariance.

As for the principle of equivalence, that is something else, unrelated
to covariance. Empirically they have been found to be identical, plus
it is required in Newtonian mechanics in order to have stable orbits.

Even now, there are still experiments directly testing the principle of
equivalence. A finding of a departure from it would be very big news!



-- 


Dr Russell StandishPhone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Senior Research Fellowhpco...@hpcoders.com.au
Economics, Kingston University http://www.hpcoders.com.au


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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 11:39 am, smitra wrote:

On 11-12-2017 23:11, Bruce Kellett wrote:

On 12/12/2017 1:51 am, smitra wrote:

On 11-12-2017 15:12, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:


On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never  
become a pure alive, or dead cat. It will only seems so for  
anyone looking at the cat, in the {alive, dead} 
base/apparatus.  Superposition never disappear, and a coin 
moree or less with a precise position, is always a 
superposition of a coin with more  or less precise momenta. The 
relation is given by the Fourier  transforms, which gives the 
relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the  
uncertainty relations give uncertainties in positions and/or  
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but 
irrelevant  for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot 
this  out, as you do regularly, I know that your purpose is to 
obfuscate,  and hide the fact that you have no rational argument 
to offer.


You confuse physics and metaphysics. The difference is not rhetorical,
 but fundamental in this thread.



We actually do detect quantum uncertainties for macroscopic objects 
routinely when doing typical quantum experiments. Interference 
experiments involving photons is a good example. Suppose we have an 
interferometer that has mirrors in it, the photons bounce off the 
mirrors and at some spot the different possible paths come together 
and you can then detect or not detect photons there.


One can then ask why the momentum absorbed by the mirror when a 
photon bounces off it, does not destroy the interference pattern. 
One may consider here a thought experiment where the mirrors are 
freely floating in a magnetic field. But that's not actually 
necessary, if you could in principle detect the momentum from the 
recoil of the photons, then you won't get interference and in 
general the interference becomes weaker if you can in principle get 
partial information.


The answer to this question is that macroscopic objects such as the 
mirror in interferometers do not have sharply defined momenta. In 
fact, you could argue that unless the mirror surface is not located 
to well within the wavelength of light, you obviously wouldn't get 
interference, and applying the uncertainty relations then also gives 
you an uncertainty in the momentum. But this doesn't tell you what 
the uncertainty in the momentum typically is.


The uncertainty in the center of mass position can be estimated 
crudely as the thermal De-Broglie wavelength. A displacement well 
within this length scale will not lead to the environment 
interacting appreciably differently with it. So, the uncertainty in 
the position will be of the order of h/sqrt(m k T). The 
interpretation is then that a wavefunction spreading beyond this 
length will effectively collapse back to within this length scale 
due to the environment effectively having located the center of mass 
within this scale.


The uncertainty in the momentum is then of the order of sqrt(m k T), 
and this can actually be quite large for large objects. This large 
uncertainty in the momentum in absolute terms explains why you can 
actually do quantum experiments using macroscopic measurement devices.


There is a fairly serious error in your analysis. You use an
expression for the momentum, p = mv = sqrt(3mkT), which applies to
molecules in an ideal gas. Mirrors in quantum experiments are not
molecules in an ideal gas! What is more, molecules in an ideal gas are
not located within their de Broglie wavelengths. You forget that the
uncertainty principle applies to the uncertainty in measurement
results, and the molecules of the gas are not constrained such that
their position uncertainty is that small.

In other words, you are talking nonsense.



No, your arguments are totally wrong here.

 The thermal de Broglie wavelength is a measure for the coherence 
length of the molecules in a gas and this then gives the coherence 
length in momentum space via the uncertainty relation


No, the de Broglie wavelength is the wavelength, not the coherence 
length. The coherence length is given by the size of the wave packet, so 
for photons, the coherence length is often orders of magnitude greater 
than the wavelength.


(if you want to invoke measurement here, you can say that the 
environment consisting of all other molecules effectively "measure" 
the position of the center of mass). To a good approximation this also 
applies to atoms in a solid, the fact that a solid is not an ideal gas 
doesn't actually matter all that much for the coherence length.


So, the mistake you made here is to assume that the coherence length 
is given 

Re: Consistency of Postulates of QM

[agrayson2000]

On Tuesday, December 12, 2017 at 1:04:08 AM UTC, Bruce wrote:
>
> On 12/12/2017 11:44 am, smitra wrote: 
> > On 11-12-2017 23:15, Bruce Kellett wrote: 
> >> On 12/12/2017 1:12 am, Bruno Marchal wrote: 
> >>> On 10 Dec 2017, at 23:38, Bruce Kellett wrote: 
>  On 11/12/2017 2:19 am, Bruno Marchal wrote: 
> > On 09 Dec 2017, at 00:03, Bruce Kellett wrote: 
> >> On 9/12/2017 4:21 am, Bruno Marchal wrote: 
> >>> Similarly, a shroedinger car, once alive + dead, will never 
> >>> become a pure alive, or dead cat. It will only seems so for 
> >>> anyone looking at the cat, in the {alive, dead} base/apparatus. 
> >>> Superposition never disappear, and a coin moree or less with a 
> >>> precise position, is always a superposition of a coin with more 
> >>> or less precise momenta. The relation is given by the Fourier 
> >>> transforms, which gives the relative accessible states/worlds. 
> >> 
> >> I pointed out that for a macroscopic object such as a coin, the 
> >> uncertainty relations give uncertainties in positions and/or 
> >> momentum far below any level of possible detection. 
> > 
> > Of possible practical detection. That is good FAPP, but irrelevant 
> > for theoretical consideration. 
>  
>  This is a purely rhetorical objection, Bruno. And when you trot 
>  this out, as you do regularly, I know that your purpose is to 
>  obfuscate, and hide the fact that you have no rational argument to 
>  offer. 
> >>> 
> >>> You confuse physics and metaphysics. The difference is not 
> >>> rhetorical, but fundamental in this thread. 
> >> 
> >> Rubbish. The central point of contention on this thread is whether a 
> >> coin toss can be regarded as a classical event, with probabilities 
> >> given by ignorance of the initial conditions, or as a quantum event 
> >> with probabilities given by purely quantum uncertainties. 
> >> 
> >> This is a straightforward question of physics, and has nothing to do 
> >> with metaphysics. As usual, you introduce the term 'metaphysics' 
> >> merely to obfuscate, because you have no intelligent response to the 
> >> clear physics of the situation. 
> >> 
> > 
> > That the probabilities are given by classical physics does not imply 
> > that there is no branching due to the coin toss. 
>
> It does, because there is no superposition of head/tails -- no 
> possibility of interference between heads and tails. 
>
> Bruce 
>

Why no inference? Is it because the coin isn't an isolated system, which 
IIUC is a necessary condition for interference? AG 

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 11:44 am, smitra wrote:

On 11-12-2017 23:15, Bruce Kellett wrote:

On 12/12/2017 1:12 am, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:

On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:

Similarly, a shroedinger car, once alive + dead, will never
become a pure alive, or dead cat. It will only seems so for
anyone looking at the cat, in the {alive, dead} base/apparatus.
Superposition never disappear, and a coin moree or less with a
precise position, is always a superposition of a coin with more
or less precise momenta. The relation is given by the Fourier
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the
uncertainty relations give uncertainties in positions and/or
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot
this out, as you do regularly, I know that your purpose is to
obfuscate, and hide the fact that you have no rational argument to
offer.


You confuse physics and metaphysics. The difference is not
rhetorical, but fundamental in this thread.


Rubbish. The central point of contention on this thread is whether a
coin toss can be regarded as a classical event, with probabilities
given by ignorance of the initial conditions, or as a quantum event
with probabilities given by purely quantum uncertainties.

This is a straightforward question of physics, and has nothing to do
with metaphysics. As usual, you introduce the term 'metaphysics'
merely to obfuscate, because you have no intelligent response to the
clear physics of the situation.



That the probabilities are given by classical physics does not imply
that there is no branching due to the coin toss.


It does, because there is no superposition of head/tails -- no 
possibility of interference between heads and tails.


Bruce

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Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 23:24, Bruce Kellett wrote:

On 11/12/2017 10:30 pm, smitra wrote:

On 11-12-2017 03:08, Bruce Kellett wrote:

On 11/12/2017 12:21 pm, smitra wrote:

On 11-12-2017 00:55, Bruce Kellett wrote:


What you have to do if you want to claim that all chance outcomes 
are

of quantum origin is compare the relative magnitudes of quantum and
thermal fluctuations at room temperature -- room temperature 
because

that is where we do the experiments. And you haven't done that;
neither has Albrecht in the paper you reference. That is why his 
paper

is a load of nonsense.


Thermal fluctuations do not need to be eliminated, as they are of 
pure quantum mechanical origin. However, if one has to argue about 
that then one loses the point of the proposed experiment. At 
absolute zero the thermal fluctuations are due to zero point motion, 
take e.g. the harmonic oscillator which then has an energy of 1/2 
hbar omega.


In generic non-integrable systems you'll have chaotic behavior where 
small perturbations grow exponentially.


Not necessarily. It depends on the relevant Lyapunov exponents. The
mean speed of molecules in a gas does not grow exponentially.



Typically the exponents are positive, there is a vast literature on 
this subject with some exactly solved cases, e.g. oddly shaped 
billiard balls.




Thermal fluctuations will then originate from quantum fluctuations.


Why then are thermal fluctuations temperature dependent? But be that
as it may, thermal fluctuations, and the random motions of molecules
in a gas, say, are not coherent, and there are no interference 
effects

between the molecules of a gas. Consequently, whatever their origin,
the motion is manifestly classical at room temperature.



Interference is a straw man. It's totally irrelevant whether or not 
some particular quantum aspects shows up in an experiment. Thing is 
that classical mechanics has already been falsified experimentally, so 
it's wrong to invoke a classical picture of what's going as a 
fundamental truth and put the burden of proof each time on a QM 
picture when it's not readily visible.


That is completely wrong-headed. Classical physics is perfectly good
for everyday situations, and for putting a probe in orbit around
Saturn. All the calculations of trajectories are done classically --
general relativity is completely irrelevant for the orbit of Saturn --
GR effects are barely detectable for the orbit of Mercury!

There is a philosophical point that any theory that has been shown not
to apply universally, has technically been falsified. But most
philosophers acknowledge that classical theories have not been
falsified in their appropriate realms of applicability. So you merely
obfuscate by claiming that we cannot use classical physics in those
situations, merely because the theory does not apply in other
situations.

QM + decoherence only allows you to use classical reasoning to compute 
macroscopic observables with negligible errors, but this does not 
means that the macroscopic physical world is classical. It's just like 
the fact that GR reduces to classical mechanics, as far as the results 
of computations are concerned, but GR is still correct and the 
classical picture is still wrong no matter how weak the gravitational 
fields are.


As I have said before, the biggest challenge for quantum physics is to
explain the emergence of the classical world from the quantum
substrate, so that classical calculations actually get the correct
answers in those classical situations. If you do not believe that
these classical calculations are correct, then I advise you not ever
to drive your car on a busy road.



There is no way a Hilbert space can become a classical configuration 
space. If one sticks to a  falsified theory (in the domain where you can 
hide the shortcomings under the carpet) and cast doubt on a theory that 
has withstood rigorous experimental tests, then it's likely that 
attitude that's the cause of most problems.


Saibal

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Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 23:15, Bruce Kellett wrote:

On 12/12/2017 1:12 am, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:

On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never become 
a pure alive, or dead cat. It will only seems so for anyone 
looking at the cat, in the {alive, dead} base/apparatus. 
Superposition never disappear, and a coin moree or less with a 
precise position, is always a superposition of a coin with more or 
less precise momenta. The relation is given by the Fourier 
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the 
uncertainty relations give uncertainties in positions and/or 
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant 
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot this 
out, as you do regularly, I know that your purpose is to obfuscate, 
and hide the fact that you have no rational argument to offer.


You confuse physics and metaphysics. The difference is not rhetorical, 
but fundamental in this thread.


Rubbish. The central point of contention on this thread is whether a
coin toss can be regarded as a classical event, with probabilities
given by ignorance of the initial conditions, or as a quantum event
with probabilities given by purely quantum uncertainties.

This is a straightforward question of physics, and has nothing to do
with metaphysics. As usual, you introduce the term 'metaphysics'
merely to obfuscate, because you have no intelligent response to the
clear physics of the situation.



That the probabilities are given by classical physics does not imply 
that there is no branching due to the coin toss.


Saibal

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Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 23:11, Bruce Kellett wrote:

On 12/12/2017 1:51 am, smitra wrote:

On 11-12-2017 15:12, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:


On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never  
become a pure alive, or dead cat. It will only seems so for  
anyone looking at the cat, in the {alive, dead} base/apparatus.  
Superposition never disappear, and a coin moree or less with a 
precise position, is always a superposition of a coin with more  
or less precise momenta. The relation is given by the Fourier  
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the  
uncertainty relations give uncertainties in positions and/or  
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant  
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot this 
 out, as you do regularly, I know that your purpose is to obfuscate, 
 and hide the fact that you have no rational argument to offer.


You confuse physics and metaphysics. The difference is not 
rhetorical,

 but fundamental in this thread.



We actually do detect quantum uncertainties for macroscopic objects 
routinely when doing typical quantum experiments. Interference 
experiments involving photons is a good example. Suppose we have an 
interferometer that has mirrors in it, the photons bounce off the 
mirrors and at some spot the different possible paths come together 
and you can then detect or not detect photons there.


One can then ask why the momentum absorbed by the mirror when a photon 
bounces off it, does not destroy the interference pattern. One may 
consider here a thought experiment where the mirrors are freely 
floating in a magnetic field. But that's not actually necessary, if 
you could in principle detect the momentum from the recoil of the 
photons, then you won't get interference and in general the 
interference becomes weaker if you can in principle get partial 
information.


The answer to this question is that macroscopic objects such as the 
mirror in interferometers do not have sharply defined momenta. In 
fact, you could argue that unless the mirror surface is not located to 
well within the wavelength of light, you obviously wouldn't get 
interference, and applying the uncertainty relations then also gives 
you an uncertainty in the momentum. But this doesn't tell you what the 
uncertainty in the momentum typically is.


The uncertainty in the center of mass position can be estimated 
crudely as the thermal De-Broglie wavelength. A displacement well 
within this length scale will not lead to the environment interacting 
appreciably differently with it. So, the uncertainty in the position 
will be of the order of h/sqrt(m k T). The interpretation is then that 
a wavefunction spreading beyond this length will effectively collapse 
back to within this length scale due to the environment effectively 
having located the center of mass within this scale.


The uncertainty in the momentum is then of the order of sqrt(m k T), 
and this can actually be quite large for large objects. This large 
uncertainty in the momentum in absolute terms explains why you can 
actually do quantum experiments using macroscopic measurement devices.


There is a fairly serious error in your analysis. You use an
expression for the momentum, p = mv = sqrt(3mkT), which applies to
molecules in an ideal gas. Mirrors in quantum experiments are not
molecules in an ideal gas! What is more, molecules in an ideal gas are
not located within their de Broglie wavelengths. You forget that the
uncertainty principle applies to the uncertainty in measurement
results, and the molecules of the gas are not constrained such that
their position uncertainty is that small.

In other words, you are talking nonsense.



No, your arguments are totally wrong here.

 The thermal de Broglie wavelength is a measure for the coherence length 
of the molecules in a gas and this then gives the coherence length in 
momentum space via the uncertainty relation (if you want to invoke 
measurement here, you can say that the environment consisting of all 
other molecules effectively "measure" the position of the center of 
mass). To a good approximation this also applies to atoms in a solid, 
the fact that a solid is not an ideal gas doesn't actually matter all 
that much for the coherence length.


So, the mistake you made here is to assume that the coherence length is 
given by the volume a molecule is known to be in, which is obviously 
wrong.


Saibal





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Re: Equivalence Principle and Einstein Field Equations

[Brent Meeker]

On 12/11/2017 2:19 PM, agrayson2...@gmail.com wrote:



What is the connection between the Equivalence Principle and
Einstein's Field Equations?


It led to the idea that force-free paths in space could be
geodesic paths in spacetime, so the apparent acceleration falling
objects could be modelled by geodesic paths in curved spacetime.


*Insofar as acceleration results / causes curved paths in space-time, 
as seen by a simple space-time diagram, one can invoke the EP to link 
acceleration to gravity -- but we already knew that! So what gave 
Einstein the idea that gravity warps space-time? AG *


Gravity causes acceleration in the Newtonian sense.  But if spacetime is 
warped this apparent curvature can be inertial motion. The advantage of 
this view is it automatically entails that everything falls with the 
same "acceleration" per the Etovos results.


Brent

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Re: Cosmological Red Shift

[agrayson2000]

On Monday, December 11, 2017 at 3:09:19 PM UTC, Lawrence Crowell wrote:
>
> On Sunday, December 10, 2017 at 8:07:15 PM UTC-6, Brent wrote:
>>
>>
>>
>> On 12/10/2017 5:25 PM, Lawrence Crowell wrote:
>>
>>
>>
>> On Sunday, December 10, 2017 at 5:13:38 PM UTC-6, agrays...@gmail.com 
>> wrote: 
>>>
>>>
>>>
>>> On Sunday, December 10, 2017 at 10:54:11 PM UTC, Lawrence Crowell wrote: 



 On Sunday, December 10, 2017 at 3:34:33 PM UTC-6, agrays...@gmail.com 
 wrote: 
>
>
>
> On Saturday, December 9, 2017 at 2:17:38 PM UTC, Lawrence Crowell 
> wrote: 
>>
>> On Saturday, December 9, 2017 at 7:34:29 AM UTC-6, 
>> agrays...@gmail.com wrote: 
>>>
>>>
>>> I think you're making the unwarranted assumption that the measured 
>>> shift in H is not 
>>> effected by the cosmological red shift which presumably shifts all 
>>> wave lengths. AG 
>>>
>>
>> Of course it shifts all wavelengths by the same factor. So the 
>> spectrum of atoms are shifted accordingly. With v = Hd the red shift 
>> factor 
>> is z = v/c = H(d/c). for H = 70km/s/Mpc for v = c we then have that d = 
>> c/H 
>> = 3x10^{5}km/s/(70Mpc/km/s) = 4.3x10^3Mpc = 1.4x10^{10}ly. So at z = 1 
>> there lies the cosmological horizon. We now observe galaxies with z = 8 
>> and 
>> the CMB has z = 1100. One can however thing of these photons as emitted 
>> prior to these systems crossing the horizon. 
>>
>> LC
>>
>
> Since a parsec is about 3.26 LY and the SoL is about 300,000 km/sec, 
> the event horizon should be about 300,000/70 * 3.26 * 10^6 = 13971 * 10^6 
> LY =~ 13971 MLY = 13.971 BLY. But this is a far cry from about 50 BLY, 
> which is what I think the true distance is to the event horizon. I 
> probably 
> didn't account for the intervening expansion. How is accurate calculation 
> done? TIA, AG
>

 That is about it. There is a bit with significant figures for you might 
 want to use c = 299800km/s.

 LC 

>>>
>>> But isn't the event horizon much farther out, about 50 BLY? AG 
>>>
>>
>> No that is about where the CMB surface of last scatter lies. 
>>
>>
>> To clarify, you mean where it lies "*now"*; and *"now" *means the 
>> (universe wide) time at which the CMB is 2.7degK.
>>
>> Brent
>>
>
> The photons we observe from the CMB were emitted prior to the ionized gas 
> crossing the cosmological horizon. We see it as it was 380k years after the 
> big bang, with this huge red shifting. This red shifting indicates that on 
> the Hubble frame this stuff is "way out there," in fact at about 47bly 
> beyond the horizon.
>
> LC
>

If I make the correction you suggest, I will get about 13.8 BLY for the 
event horizon, which is the distance a photon would travel if it began its 
journey at t = 0, ignoring the intervening expansion. Is this 
coincidental?  Moreover, the figure of 47 BLY is the current distance of 
the object which emitted said photon. So I don't have to worry about the 
CMB to calculate this value. I think I just need to integrate for the age 
of the universe, but I am not sure what the integrand should be. AG

>  
>
>>
>> It has z = 1100 and is further out beyond the horizon.
>>
>> LC 
>> -- 
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>>
>>
>>

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 11/12/2017 10:30 pm, smitra wrote:

On 11-12-2017 03:08, Bruce Kellett wrote:

On 11/12/2017 12:21 pm, smitra wrote:

On 11-12-2017 00:55, Bruce Kellett wrote:


What you have to do if you want to claim that all chance outcomes are
of quantum origin is compare the relative magnitudes of quantum and
thermal fluctuations at room temperature -- room temperature because
that is where we do the experiments. And you haven't done that;
neither has Albrecht in the paper you reference. That is why his paper
is a load of nonsense.


Thermal fluctuations do not need to be eliminated, as they are of 
pure quantum mechanical origin. However, if one has to argue about 
that then one loses the point of the proposed experiment. At 
absolute zero the thermal fluctuations are due to zero point motion, 
take e.g. the harmonic oscillator which then has an energy of 1/2 
hbar omega.


In generic non-integrable systems you'll have chaotic behavior where 
small perturbations grow exponentially.


Not necessarily. It depends on the relevant Lyapunov exponents. The
mean speed of molecules in a gas does not grow exponentially.



Typically the exponents are positive, there is a vast literature on 
this subject with some exactly solved cases, e.g. oddly shaped 
billiard balls.




Thermal fluctuations will then originate from quantum fluctuations.


Why then are thermal fluctuations temperature dependent? But be that
as it may, thermal fluctuations, and the random motions of molecules
in a gas, say, are not coherent, and there are no interference effects
between the molecules of a gas. Consequently, whatever their origin,
the motion is manifestly classical at room temperature.



Interference is a straw man. It's totally irrelevant whether or not 
some particular quantum aspects shows up in an experiment. Thing is 
that classical mechanics has already been falsified experimentally, so 
it's wrong to invoke a classical picture of what's going as a 
fundamental truth and put the burden of proof each time on a QM 
picture when it's not readily visible.


That is completely wrong-headed. Classical physics is perfectly good for 
everyday situations, and for putting a probe in orbit around Saturn. All 
the calculations of trajectories are done classically -- general 
relativity is completely irrelevant for the orbit of Saturn -- GR 
effects are barely detectable for the orbit of Mercury!


There is a philosophical point that any theory that has been shown not 
to apply universally, has technically been falsified. But most 
philosophers acknowledge that classical theories have not been falsified 
in their appropriate realms of applicability. So you merely obfuscate by 
claiming that we cannot use classical physics in those situations, 
merely because the theory does not apply in other situations.


QM + decoherence only allows you to use classical reasoning to compute 
macroscopic observables with negligible errors, but this does not 
means that the macroscopic physical world is classical. It's just like 
the fact that GR reduces to classical mechanics, as far as the results 
of computations are concerned, but GR is still correct and the 
classical picture is still wrong no matter how weak the gravitational 
fields are.


As I have said before, the biggest challenge for quantum physics is to 
explain the emergence of the classical world from the quantum substrate, 
so that classical calculations actually get the correct answers in those 
classical situations. If you do not believe that these classical 
calculations are correct, then I advise you not ever to drive your car 
on a busy road.


Bruce

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Re: Equivalence Principle and Einstein Field Equations

[agrayson2000]

On Sunday, December 10, 2017 at 10:43:27 PM UTC, Brent wrote:
>
>
>
> On 12/10/2017 8:49 AM, agrays...@gmail.com  wrote:
>
> What is the connection between the Equivalence Principle and Einstein's 
> Field Equations? 
>
>
> It led to the idea that force-free paths in space could be geodesic paths 
> in spacetime, so the apparent acceleration falling objects could be 
> modelled by geodesic paths in curved spacetime. 
>

*Insofar as acceleration results / causes curved paths in space-time, as 
seen by a simple space-time diagram, one can invoke the EP to link 
acceleration to gravity -- but we already knew that! So what gave Einstein 
the idea that gravity warps space-time? AG  *

>
> How did the former lead to the latter? Why was the man falling from the 
> ladder so decisive in leading to the Theory of General Relativity? TIA, AG
>
>
> You have asked for a "connection" and then you imply that one "led to" GR 
> and finally predicated a question on the "connection" being "decisive" in 
> leading to GR.  The "connection" is just one of suggesting an idea.  
>
> Brent
>
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>
>

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 1:12 am, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:

On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never become 
a pure alive, or dead cat. It will only seems so for anyone 
looking at the cat, in the {alive, dead} base/apparatus. 
Superposition never disappear, and a coin moree or less with a 
precise position, is always a superposition of a coin with more or 
less precise momenta. The relation is given by the Fourier 
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the 
uncertainty relations give uncertainties in positions and/or 
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant 
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot this 
out, as you do regularly, I know that your purpose is to obfuscate, 
and hide the fact that you have no rational argument to offer.


You confuse physics and metaphysics. The difference is not rhetorical, 
but fundamental in this thread.


Rubbish. The central point of contention on this thread is whether a 
coin toss can be regarded as a classical event, with probabilities given 
by ignorance of the initial conditions, or as a quantum event with 
probabilities given by purely quantum uncertainties.


This is a straightforward question of physics, and has nothing to do 
with metaphysics. As usual, you introduce the term 'metaphysics' merely 
to obfuscate, because you have no intelligent response to the clear 
physics of the situation.


Bruce

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Re: Equivalence Principle and Einstein Field Equations

[agrayson2000]

On Sunday, December 10, 2017 at 11:41:21 PM UTC, John Clark wrote:
>
>
>
> On Sun, Dec 10, 2017 at 4:42 PM,  
> wrote:
>
> ​> ​
>> What is the connection between the Equivalence Principle and Einstein's 
>> Field Equations? How did the former lead to the latter? Why was the man 
>> falling from the ladder so decisive in leading to the Theory of General 
>> Relativity? 
>>
>
>
> The Equivalence Principle says if 
> ​you
>  ignore tidal effects and you're in a windowless elevator cab there is no 
> way to know if you're sitting on the Earth in a gravitational field or in 
> deep intergalactic space being accelerated by a rocket upward at 1G. If you 
> feel zero G and fire a Laser pointer from one wall 
> ​to the other ​
> it will go in a straight line and hit the exact opposite side on the other 
> wall. But if you were being accelerated upward the elevator cab will move 
> ​slightly ​
> upward in the time it takes for the light to go from one wall to the other 
> so the spot the laser makes on the other wall will be slightly lower than 
> it was when you were in zero G, you see the laser beam follow a curve.
>

At rest on Earth is not a situation of zero G; it's 1G. Or, say, if you 
want a straight beam, one can assume an inertial frame, and of course, in 
either frame one will observe the beam as straight. AG 

>
> A curved line from one wall to the other is longer than a straight line
> ​,​
> and yet when you measure the time it takes for light to do this with your 
> very accurate clock you notice its exactly the same. You already know the 
> measured speed of light never changes so 
> ​if something is moving at the same speed and moves a greater distance in 
> the same number of clock ticks then 
> you'd have to conclude that being accelerated makes your clock run slow.
>


I think most of last paragraph incorrect. In experiments with GPS clocks, 
the ground clock, in the stronger gravity field, runs slower than an 
orbiting clock. Fewer ticks in ground clock, which is objectively behind 
the orbiting clock. In your elevator example, where zero G can be 
interpreted as being in an inertial frame, you claim the elapsed time 
duration using ticks, is identical for both beams. This contradicts GPS 
experiments if we assume for direct comparison that the orbiting clock is 
very far from Earth, effectively in the weaker (zero) gravity field. AG 

> And because of the Equivalence Principle you'd have to 
> ​also ​
> conclude that a gravitational field bends light and makes time run slow 
> ​just as acceleration does.​
>
> ​John K Clark​
>
>
>
>  
>

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Re: Consistency of Postulates of QM

[Bruce Kellett]

On 12/12/2017 1:51 am, smitra wrote:

On 11-12-2017 15:12, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:


On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never  
become a pure alive, or dead cat. It will only seems so for  
anyone looking at the cat, in the {alive, dead} base/apparatus.  
Superposition never disappear, and a coin moree or less with a 
precise position, is always a superposition of a coin with more  
or less precise momenta. The relation is given by the Fourier  
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the  
uncertainty relations give uncertainties in positions and/or  
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant  
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot 
this  out, as you do regularly, I know that your purpose is to 
obfuscate,  and hide the fact that you have no rational argument to 
offer.


You confuse physics and metaphysics. The difference is not rhetorical,
 but fundamental in this thread.



We actually do detect quantum uncertainties for macroscopic objects 
routinely when doing typical quantum experiments. Interference 
experiments involving photons is a good example. Suppose we have an 
interferometer that has mirrors in it, the photons bounce off the 
mirrors and at some spot the different possible paths come together 
and you can then detect or not detect photons there.


One can then ask why the momentum absorbed by the mirror when a photon 
bounces off it, does not destroy the interference pattern. One may 
consider here a thought experiment where the mirrors are freely 
floating in a magnetic field. But that's not actually necessary, if 
you could in principle detect the momentum from the recoil of the 
photons, then you won't get interference and in general the 
interference becomes weaker if you can in principle get partial 
information.


The answer to this question is that macroscopic objects such as the 
mirror in interferometers do not have sharply defined momenta. In 
fact, you could argue that unless the mirror surface is not located to 
well within the wavelength of light, you obviously wouldn't get 
interference, and applying the uncertainty relations then also gives 
you an uncertainty in the momentum. But this doesn't tell you what the 
uncertainty in the momentum typically is.


The uncertainty in the center of mass position can be estimated 
crudely as the thermal De-Broglie wavelength. A displacement well 
within this length scale will not lead to the environment interacting 
appreciably differently with it. So, the uncertainty in the position 
will be of the order of h/sqrt(m k T). The interpretation is then that 
a wavefunction spreading beyond this length will effectively collapse 
back to within this length scale due to the environment effectively 
having located the center of mass within this scale.


The uncertainty in the momentum is then of the order of sqrt(m k T), 
and this can actually be quite large for large objects. This large 
uncertainty in the momentum in absolute terms explains why you can 
actually do quantum experiments using macroscopic measurement devices.


There is a fairly serious error in your analysis. You use an expression 
for the momentum, p = mv = sqrt(3mkT), which applies to molecules in an 
ideal gas. Mirrors in quantum experiments are not molecules in an ideal 
gas! What is more, molecules in an ideal gas are not located within 
their de Broglie wavelengths. You forget that the uncertainty principle 
applies to the uncertainty in measurement results, and the molecules of 
the gas are not constrained such that their position uncertainty is that 
small.


In other words, you are talking nonsense.

Bruce

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Re: Consistency of Postulates of QM

[Brent Meeker]

On 12/11/2017 12:11 PM, smitra wrote:

On 11-12-2017 20:03, Brent Meeker wrote:

On 12/11/2017 3:48 AM, smitra wrote:


On 10-12-2017 23:09, Brent Meeker wrote:
On 12/10/2017 4:42 AM, smitra wrote:
On 09-12-2017 21:18, Brent Meeker wrote:
On 12/9/2017 4:00 AM, smitra wrote:
On 09-12-2017 12:01, Bruce Kellett wrote:
On 9/12/2017 9:44 pm, smitra wrote:
On 09-12-2017 02:48, Bruce Kellett wrote:
On 9/12/2017 11:49 am, smitra wrote:
On 09-12-2017 00:03, Bruce Kellett wrote:
On 9/12/2017 4:21 am, Bruno Marchal wrote:
On 08 Dec 2017, at 00:22, Bruce Kellett wrote:
On 8/12/2017 3:31 am, Bruno Marchal wrote:
On 06 Dec 2017, at 12:19, Bruce Kellett wrote:

But as I pointed out, thermal motion gives momenta of magnitudes
such that the quantum uncertainties are negligible compared to the
thermal randomness. And thermal motions are not coherent.

You seem to work in Bohr QM, with some dualism between the quantum
reality and the classical reality.


 Not at all. The (semi-)classical world emerges from the quantum
substrate; if you cannot give an account of this, then you have failed
to explain our everyday experience. And explaining that experience is
the purpose of physics.

 No problem with this, except for your usual skepticism of Everett's
program (say).

 Skepticism is the scientific stance.


You are right that this does not change anything FAPP, but our
discussion is not about practical applications, but metaphysics.

No, we were talking about tossing a coin, we were not talking about
metaphysics. Your metaphysics has served merely to confuse you to
the extent that you do not understand even the simplest physics.


 That is ad hominem remark which I take as absence of argument.

 You don't take kindly to criticism, do you Bruno?


All I said is that without collapse, shaking a box with some coin
long enough would lead to the superposition of the two coin state.
You seem to be the one confusing the local decoherence with some
collapse. The Heisenberg uncertainties are great enough to amplify
slight change of the move of the coin when bouncing on the wall.


 That is simply assertion on your part, without a shred of argument or

 justification. When one looks at the arguments, such as that put
 forward by Albrecht and David (referred to by smitra), one finds that

 the emperor has no clothes!


Similarly, a shroedinger car, once alive + dead, will never become a
pure alive, or dead cat. It will only seems so for anyone looking at
the cat, in the {alive, dead} base/apparatus. Superposition never
disappear, and a coin moree or less with a precise position, is
always a superposition of a coin with more or less precise momenta.
The relation is given by the Fourier transforms, which gives the
relative accessible states/worlds.


 I pointed out that for a macroscopic object such as a coin, the
 uncertainty relations give uncertainties in positions and/or momentum

 far below any level of possible detection. And I gave an argument
with
 an actual calculation -- not just an assertion. Uncertainties in the
 constituents of the object are uncorrelated, random, and cancel out.
 So although the superposition originating from the big bang is intact

 from the bird's point of view, it is so completely irrelevant for
 everyday purposes that it is an insult to even refer to the
 classicality of the world as FAPP -- it is complete. Relying on the
 charge of "FAPP" as a justification for your assertions is nonsense.

 It's not irrelevant if you don't have the information that locates
you in a sector where the uncertainties are indeed small enough. You
have to start with the complete state in the bird's view, and then
consider the sector where you have some definite information and then
project onto that subspace. If you do that, then your coins are not at
all in a precisely enough classical state but rather in superpositions
(entangled with the environment) that lead to wildly different
outcomes of coin tosses.

 E.g. in the bird's view there exists exact copies of me that live on
planets that are not the same, some will have a radius of a few
millimeter larger than others. Here exact copy means exactly the same
conscious experience, which is then due to exactly the same
computational state of the brain described by some bitstring that's
exactly the same.

 So, from totally different decoherent branches of the wavefunction
one can factor out some bitstring describing a conscious experience,
the reduced state of the rest of the universe in that sector is then a
superposition of a many different effectively classical states.

 If this were not true then each single conscious experience would
contain in it information about such things as the exact  number of
atoms in the Earth, Sun etc. etc.

 I prefer to live in the real world, so I would rather not indulge
your
 fantasies.

 The real world is not what you think it is. It was only when you read
about the fact that dinosaurs had once existed that the sector you
were in 

Re: Consistency of Postulates of QM

[agrayson2000]

On Sunday, December 10, 2017 at 5:26:32 PM UTC, John Clark wrote:
>
> On Fri, Dec 8, 2017 at 2:15 AM,  wrote:
>
> ​> ​
>> The fundamental unproven assumption, and IMO the core fallacy of the MWI, 
>> is the belief that what CAN occur, necessarily MUST will occur.
>>
>
> The
> ​ ​
> fundamental
> ​ ​
> assumption of the MWI is that the
> ​ ​
> Schrodinger 
> ​Wave
>  
> ​Equation
>  means what it says and says what it means. The ​
> ​
> fundamental
> ​ ​
> assumption
> ​ of Copenhagen is that ​
> Schrodinger
> ​ forgot to put a "except" and a "however" into his equation.​
>

Solutions of the SWE give the probabilities of getting possible measurement 
outcomes prior to the measurement. If you want to give the equation a life 
after measurement, why not do it in THIS world where the probability wave 
becomes entangled with the environment? Why the need for other worlds? MWI 
seems to make a difficult problem much worse. Can't you see that? ... Do 
you know about Gleason's result which Brent mentioned. He seemed to claim 
it negated the main claim of MWI, that everything that CAN happen, DOES 
happen. AG 

>  
>
>> ​> ​
>> I don't object to unknown natural processes creating universes, but when 
>> a human is claimed to have the ability to do it
>> ​ 
>>
>
> ​A human is just as natural as any other process.​
>  
> ​
>  
>
>> ​> ​
>> how do you justify this apparent absurdity?
>>
>
> ​Experimental results have proven beyond all doubt that the fundamental 
> laws of physics *ARE* absurd but don't complain to me, complain to God 
> about it if you know His current Email address, He used to be on AOL but I 
> think He changed it.
>

The idea of general covariance as a principle for understanding the natural 
world is not in the least absurd. You seem to adopt a pov which reminds me 
of religious zealots, who defend poorly founded ideas by appeals to 
ignorance of God's behavior. AG

>  
>
>> ​> ​
>> I was asserting is that in Copenhagen you don't need a conscious observer 
>> to get a measurement outcome.
>>
>
> ​Show me how to measure something without anybody doing any measuring and 
> show me the new term you added to the Schrodinger Equation that causes it 
> to collapse when a measurement is taken.
>

I've been saying all along that a conscious observer is not needed to 
create or destroy the interference, which is what the issue of conscious 
observers is about. IOW, collapse or no collapse has nothing to do with the 
existence of humans. Of course, one needs a human to set up the measurement 
device. That was never an issue. AG 

>
>  
>>> ​>> ​
>>> T
>>> he Schrodinger Wave Equation
>>> ​ says absolutely nothing about collapsing and yet you insist it does, 
>>>
>>
>> ​> ​
>> I never made that assertion. I just said we observe a collapse
>>
>
> So
> ​ ​t
> he Schrodinger Wave Equation
> ​ doesn't collapse we just observe it collapsing but conscious observers 
> have nothing to do with it?? I said the laws of physics were absurd I did 
> not say they were paradoxical. ​
>
>  
>
>> ​>> ​
>>> He proved the mathematical consistency of this idea by adding up all the 
>>> probabilities in all the branches of the event happening and getting 
>>> exactly 100%.  
>>>
>>
>> ​> ​
>> Interesting. But how can he add them up if there are uncountably many 
>> universes?
>>
>
> ​That's what calculus is for.​
>  
>

I know. For some reason or other I was assuming the probabilities were 
estimated statistically whereas the set of possible outcomes is 
uncountable. BTW, did MWI derive Born's rule, or did it simply argue for 
its plausibility? Even the latter would be an interesting result, but not 
nearly enough to make the interpretation palatable. AG  

> ​
>
>  John K Clark​
>
>
>
>
>  
>

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Re: Equivalence Principle and Einstein Field Equations

[agrayson2000]

On Monday, December 11, 2017 at 9:14:09 AM UTC, Russell Standish wrote:
>
> On Sun, Dec 10, 2017 at 07:06:00PM -0800, agrays...@gmail.com 
>  wrote: 
> > Excellent summary. TY. But why would Einstein think there could be a 
> > covariant theory for accelerating frames when an observer inside such a 
> > frame can do measurements to confirm acceleration and differences with 
> > other such frames, unlike the case for inertial frames which are clearly 
> > equivalent? AG 
>
> If I have a tensor equation like C=\sum_{ij} A_{ij}B_{ij} where C is a 
> scalar quantity, then the coefficients of A and B must "covary" with 
> each other as you select different coordinate systems, since C must 
> remain unchanged regardless of coordinate system. Given the 
> setting is spacetime, that includes rotations in the time dimension 
> too, which is equivalent to changes in inertial reference frame by 
> velocity boost. 
>
> This is really obvious if we use things like the 4 dimensional dot 
> product, but traditional tensor equations are written in component 
> form, so one must ensure the covariance property is preserved to have 
> a valid equation. Indeed, in the above equation, superscripts are used 
> to represent the covariant indices, ie 
>
>   C = A_{ij}B^{ij} 
>
> where the summation sign is dropped, since it is obvious from the way 
> the equation is written. 
>

*IIUC, you're saying that tensors transform covariantly, that is, 
independent of coordinate system, but you haven't addressed my question why 
Einstein would think accelerating frames are equivalent, or why a theory of 
gravity could be, or must be covariant. BTW, is it correct to say that 
"covariance" is a synonym for "Lorentz invariant"? TIA, AG*

>
>
> -- 
>
>  
>
> Dr Russell StandishPhone 0425 253119 (mobile) 
> Principal, High Performance Coders 
> Visiting Senior Research Fellowhpc...@hpcoders.com.au 
>  
> Economics, Kingston University http://www.hpcoders.com.au 
>  
>
>

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Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 20:03, Brent Meeker wrote:

On 12/11/2017 3:48 AM, smitra wrote:


On 10-12-2017 23:09, Brent Meeker wrote:
On 12/10/2017 4:42 AM, smitra wrote:
On 09-12-2017 21:18, Brent Meeker wrote:
On 12/9/2017 4:00 AM, smitra wrote:
On 09-12-2017 12:01, Bruce Kellett wrote:
On 9/12/2017 9:44 pm, smitra wrote:
On 09-12-2017 02:48, Bruce Kellett wrote:
On 9/12/2017 11:49 am, smitra wrote:
On 09-12-2017 00:03, Bruce Kellett wrote:
On 9/12/2017 4:21 am, Bruno Marchal wrote:
On 08 Dec 2017, at 00:22, Bruce Kellett wrote:
On 8/12/2017 3:31 am, Bruno Marchal wrote:
On 06 Dec 2017, at 12:19, Bruce Kellett wrote:

But as I pointed out, thermal motion gives momenta of magnitudes
such that the quantum uncertainties are negligible compared to the
thermal randomness. And thermal motions are not coherent.

You seem to work in Bohr QM, with some dualism between the quantum
reality and the classical reality.


 Not at all. The (semi-)classical world emerges from the quantum
substrate; if you cannot give an account of this, then you have failed
to explain our everyday experience. And explaining that experience is
the purpose of physics.

 No problem with this, except for your usual skepticism of Everett's
program (say).

 Skepticism is the scientific stance.


You are right that this does not change anything FAPP, but our
discussion is not about practical applications, but metaphysics.

No, we were talking about tossing a coin, we were not talking about
metaphysics. Your metaphysics has served merely to confuse you to
the extent that you do not understand even the simplest physics.


 That is ad hominem remark which I take as absence of argument.

 You don't take kindly to criticism, do you Bruno?


All I said is that without collapse, shaking a box with some coin
long enough would lead to the superposition of the two coin state.
You seem to be the one confusing the local decoherence with some
collapse. The Heisenberg uncertainties are great enough to amplify
slight change of the move of the coin when bouncing on the wall.


 That is simply assertion on your part, without a shred of argument or

 justification. When one looks at the arguments, such as that put
 forward by Albrecht and David (referred to by smitra), one finds that

 the emperor has no clothes!


Similarly, a shroedinger car, once alive + dead, will never become a
pure alive, or dead cat. It will only seems so for anyone looking at
the cat, in the {alive, dead} base/apparatus. Superposition never
disappear, and a coin moree or less with a precise position, is
always a superposition of a coin with more or less precise momenta.
The relation is given by the Fourier transforms, which gives the
relative accessible states/worlds.


 I pointed out that for a macroscopic object such as a coin, the
 uncertainty relations give uncertainties in positions and/or momentum

 far below any level of possible detection. And I gave an argument
with
 an actual calculation -- not just an assertion. Uncertainties in the
 constituents of the object are uncorrelated, random, and cancel out.
 So although the superposition originating from the big bang is intact

 from the bird's point of view, it is so completely irrelevant for
 everyday purposes that it is an insult to even refer to the
 classicality of the world as FAPP -- it is complete. Relying on the
 charge of "FAPP" as a justification for your assertions is nonsense.

 It's not irrelevant if you don't have the information that locates
you in a sector where the uncertainties are indeed small enough. You
have to start with the complete state in the bird's view, and then
consider the sector where you have some definite information and then
project onto that subspace. If you do that, then your coins are not at
all in a precisely enough classical state but rather in superpositions
(entangled with the environment) that lead to wildly different
outcomes of coin tosses.

 E.g. in the bird's view there exists exact copies of me that live on
planets that are not the same, some will have a radius of a few
millimeter larger than others. Here exact copy means exactly the same
conscious experience, which is then due to exactly the same
computational state of the brain described by some bitstring that's
exactly the same.

 So, from totally different decoherent branches of the wavefunction
one can factor out some bitstring describing a conscious experience,
the reduced state of the rest of the universe in that sector is then a
superposition of a many different effectively classical states.

 If this were not true then each single conscious experience would
contain in it information about such things as the exact  number of
atoms in the Earth, Sun etc. etc.

 I prefer to live in the real world, so I would rather not indulge
your
 fantasies.

 The real world is not what you think it is. It was only when you read
about the fact that dinosaurs had once existed that the sector you
were in diverged from other sectors where dinosaurs had 

Re: Consistency of Postulates of QM

[Brent Meeker]

On 12/11/2017 3:48 AM, smitra wrote:

On 10-12-2017 23:09, Brent Meeker wrote:

On 12/10/2017 4:42 AM, smitra wrote:

On 09-12-2017 21:18, Brent Meeker wrote:

On 12/9/2017 4:00 AM, smitra wrote:

On 09-12-2017 12:01, Bruce Kellett wrote:

On 9/12/2017 9:44 pm, smitra wrote:

On 09-12-2017 02:48, Bruce Kellett wrote:

On 9/12/2017 11:49 am, smitra wrote:

On 09-12-2017 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:

On 08 Dec 2017, at 00:22, Bruce Kellett wrote:

On 8/12/2017 3:31 am, Bruno Marchal wrote:

On 06 Dec 2017, at 12:19, Bruce Kellett wrote:

But as I pointed out, thermal motion gives momenta of 
magnitudes such that the quantum uncertainties are 
negligible compared to the thermal randomness. And 
thermal motions are not coherent.


You seem to work in Bohr QM, with some dualism between the 
quantum reality and the classical reality.


Not at all. The (semi-)classical world emerges from the 
quantum substrate; if you cannot give an account of this, 
then you have failed to explain our everyday experience. 
And explaining that experience is the purpose of physics.


No problem with this, except for your usual skepticism of 
Everett's program (say).


Skepticism is the scientific stance.



You are right that this does not change anything FAPP, but 
our discussion is not about practical applications, but 
metaphysics.


No, we were talking about tossing a coin, we were not 
talking about metaphysics. Your metaphysics has served 
merely to confuse you to the extent that you do not 
understand even the simplest physics.


That is ad hominem remark which I take as absence of argument.


You don't take kindly to criticism, do you Bruno?

All I said is that without collapse, shaking a box with some 
coin long enough would lead to the superposition of the two 
coin state. You seem to be the one confusing the local 
decoherence with some collapse. The Heisenberg uncertainties 
are great enough to amplify slight change of the move of the 
coin when bouncing on the wall.


That is simply assertion on your part, without a shred of 
argument or

justification. When one looks at the arguments, such as that put
forward by Albrecht and David (referred to by smitra), one 
finds that

the emperor has no clothes!

Similarly, a shroedinger car, once alive + dead, will never 
become a pure alive, or dead cat. It will only seems so for 
anyone looking at the cat, in the {alive, dead} 
base/apparatus. Superposition never disappear, and a coin 
moree or less with a precise position, is always a 
superposition of a coin with more or less precise momenta. 
The relation is given by the Fourier transforms, which gives 
the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the
uncertainty relations give uncertainties in positions and/or 
momentum
far below any level of possible detection. And I gave an 
argument with
an actual calculation -- not just an assertion. Uncertainties 
in the
constituents of the object are uncorrelated, random, and 
cancel out.
So although the superposition originating from the big bang 
is intact
from the bird's point of view, it is so completely irrelevant 
for

everyday purposes that it is an insult to even refer to the
classicality of the world as FAPP -- it is complete. Relying 
on the
charge of "FAPP" as a justification for your assertions is 
nonsense.




It's not irrelevant if you don't have the information that 
locates you in a sector where the uncertainties are indeed 
small enough. You have to start with the complete state in the 
bird's view, and then consider the sector where you have some 
definite information and then project onto that subspace. If 
you do that, then your coins are not at all in a precisely 
enough classical state but rather in superpositions (entangled 
with the environment) that lead to wildly different outcomes 
of coin tosses.


E.g. in the bird's view there exists exact copies of me that 
live on planets that are not the same, some will have a radius 
of a few millimeter larger than others. Here exact copy means 
exactly the same conscious experience, which is then due to 
exactly the same computational state of the brain described by 
some bitstring that's exactly the same.


So, from totally different decoherent branches of the 
wavefunction one can factor out some bitstring describing a 
conscious experience, the reduced state of the rest of the 
universe in that sector is then a superposition of a many 
different effectively classical states.


If this were not true then each single conscious experience 
would contain in it information about such things as the 
exact  number of atoms in the Earth, Sun etc. etc.


I prefer to live in the real world, so I would rather not 
indulge your

fantasies.

The real world is not what you think it is. It was only when you 
read about the fact that dinosaurs had once existed that the 
sector you were in diverged from other sectors where 

Re: Cosmological Red Shift

[Lawrence Crowell]

On Sunday, December 10, 2017 at 8:07:15 PM UTC-6, Brent wrote:
>
>
>
> On 12/10/2017 5:25 PM, Lawrence Crowell wrote:
>
>
>
> On Sunday, December 10, 2017 at 5:13:38 PM UTC-6, agrays...@gmail.com 
> wrote: 
>>
>>
>>
>> On Sunday, December 10, 2017 at 10:54:11 PM UTC, Lawrence Crowell wrote: 
>>>
>>>
>>>
>>> On Sunday, December 10, 2017 at 3:34:33 PM UTC-6, agrays...@gmail.com 
>>> wrote: 



 On Saturday, December 9, 2017 at 2:17:38 PM UTC, Lawrence Crowell 
 wrote: 
>
> On Saturday, December 9, 2017 at 7:34:29 AM UTC-6, agrays...@gmail.com 
> wrote: 
>>
>>
>> I think you're making the unwarranted assumption that the measured 
>> shift in H is not 
>> effected by the cosmological red shift which presumably shifts all 
>> wave lengths. AG 
>>
>
> Of course it shifts all wavelengths by the same factor. So the 
> spectrum of atoms are shifted accordingly. With v = Hd the red shift 
> factor 
> is z = v/c = H(d/c). for H = 70km/s/Mpc for v = c we then have that d = 
> c/H 
> = 3x10^{5}km/s/(70Mpc/km/s) = 4.3x10^3Mpc = 1.4x10^{10}ly. So at z = 1 
> there lies the cosmological horizon. We now observe galaxies with z = 8 
> and 
> the CMB has z = 1100. One can however thing of these photons as emitted 
> prior to these systems crossing the horizon. 
>
> LC
>

 Since a parsec is about 3.26 LY and the SoL is about 300,000 km/sec, 
 the event horizon should be about 300,000/70 * 3.26 * 10^6 = 13971 * 10^6 
 LY =~ 13971 MLY = 13.971 BLY. But this is a far cry from about 50 BLY, 
 which is what I think the true distance is to the event horizon. I 
 probably 
 didn't account for the intervening expansion. How is accurate calculation 
 done? TIA, AG

>>>
>>> That is about it. There is a bit with significant figures for you might 
>>> want to use c = 299800km/s.
>>>
>>> LC 
>>>
>>
>> But isn't the event horizon much farther out, about 50 BLY? AG 
>>
>
> No that is about where the CMB surface of last scatter lies. 
>
>
> To clarify, you mean where it lies "*now"*; and *"now" *means the 
> (universe wide) time at which the CMB is 2.7degK.
>
> Brent
>

The photons we observe from the CMB were emitted prior to the ionized gas 
crossing the cosmological horizon. We see it as it was 380k years after the 
big bang, with this huge red shifting. This red shifting indicates that on 
the Hubble frame this stuff is "way out there," in fact at about 47bly 
beyond the horizon.

LC
 

>
> It has z = 1100 and is further out beyond the horizon.
>
> LC 
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Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 15:12, Bruno Marchal wrote:

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:


On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never  become 
a pure alive, or dead cat. It will only seems so for  anyone 
looking at the cat, in the {alive, dead} base/apparatus.  
Superposition never disappear, and a coin moree or less with a  
precise position, is always a superposition of a coin with more  or 
less precise momenta. The relation is given by the Fourier  
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the  
uncertainty relations give uncertainties in positions and/or  
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant  
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot this  
out, as you do regularly, I know that your purpose is to obfuscate,  
and hide the fact that you have no rational argument to offer.


You confuse physics and metaphysics. The difference is not rhetorical,
 but fundamental in this thread.



We actually do detect quantum uncertainties for macroscopic objects 
routinely when doing typical quantum experiments. Interference 
experiments involving photons is a good example. Suppose we have an 
interferometer that has mirrors in it, the photons bounce off the 
mirrors and at some spot the different possible paths come together and 
you can then detect or not detect photons there.


One can then ask why the momentum absorbed by the mirror when a photon 
bounces off it, does not destroy the interference pattern. One may 
consider here a thought experiment where the mirrors are freely floating 
in a magnetic field. But that's not actually necessary, if you could in 
principle detect the momentum from the recoil of the photons, then you 
won't get interference and in general the interference becomes weaker if 
you can in principle get partial information.


The answer to this question is that macroscopic objects such as the 
mirror in interferometers do not have sharply defined momenta. In fact, 
you could argue that unless the mirror surface is not located to well 
within the wavelength of light, you obviously wouldn't get interference, 
and applying the uncertainty relations then also gives you an 
uncertainty in the momentum. But this doesn't tell you what the 
uncertainty in the momentum typically is.


The uncertainty in the center of mass position can be estimated crudely 
as the thermal De-Broglie wavelength. A displacement well within this 
length scale will not lead to the environment interacting appreciably 
differently with it. So, the uncertainty in the position will be of the 
order of h/sqrt(m k T). The interpretation is then that a wavefunction 
spreading beyond this length will effectively collapse back to within 
this length scale due to the environment effectively having located the 
center of mass within this scale.


The uncertainty in the momentum is then of the order of sqrt(m k T), and 
this can actually be quite large for large objects. This large 
uncertainty in the momentum in absolute terms explains why you can 
actually do quantum experiments using macroscopic measurement devices.


Saibal

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Re: Equivalence Principle and Einstein Field Equations

[John Clark]

On Sun, Dec 10, 2017 at 10:06 PM,  wrote:

​> ​
> Excellent summary. TY. But why would Einstein think there could be a
> covariant theory for accelerating frames
>

​The speed of light doesn't change even for an accelerating observer ​nor
does the spacetime distance between 2 events.

​
Einstein figured there must be a reason why. ​
​Also, before Einstein there were 2 different kinds of mass, inertial mass
and gravitational mass, Einstein had a hunch there was really only one sort
of mass and tried to find a relation between the two. ​And he found it.


> ​> ​
> when an observer inside such a frame can do measurements to confirm
> acceleration and differences with other such frames
>

​The observer can't tell if he is accelerating or in a gravitational
 field.​



> ​> ​
> unlike the case for inertial frames which are clearly equivalent?
>

Not everything is equivalent. You and I may not be accelerating and both be
in inertial frames but if we
​ are​
moving at different velocities then 2 events that are simultaneous for me
may not be simultaneous for you. The fact that simultaneity is not the same
for everyone turns what would otherwise be a logical paradox into something
that is just very strange
​;​
if we're
​both ​
in inertial frames
​and ​
in motion with respect to each other then I see your clock running slow and
you see my clock running slow.

 John K Clark

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 11 Dec 2017, at 03:04, Brent Meeker wrote:




On 12/10/2017 5:23 PM, smitra wrote:

On 10-12-2017 22:55, Brent Meeker wrote:

On 12/10/2017 4:06 AM, smitra wrote:

On 09-12-2017 21:12, Brent Meeker wrote:

On 12/9/2017 2:36 AM, smitra wrote:
Yes, it's a different argument but it's also generically  
correct. But I do think for the discussions in this list it  
doesn't matter all that much whether an initial single branch  
will diverge into multiple branches due to effectively  
classical dynamics.


Branching due to effectively classical dynamics is a  
contradiction in

terms.  If it's effectively classical it can't branch.




Counterexample: A perfectly balanced pencil on its one atom wide  
tip.


Air turbulence will dominate which way it falls.



But air turbulence is a chaotic phenomenon so quantum fluctuations  
will eventually grow exponentially and start to affect the pencil.


This repeated appeal to chaos theory to justify a quantum source of  
randomness confuses me.


The chaos is not used to justify the quantum randomness, only to  
justify the quasi-classical local amplification of a pure microscopic  
quantum uncertainty into macorscopic but not detectable, yet "real"  
with the MW theory,  superpositions.






There is no chaos in QM.  It's a classical limit phenomenon.


Absolutely, like irreversibility.

Bruno






Brent

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 10 Dec 2017, at 23:38, Bruce Kellett wrote:


On 11/12/2017 2:19 am, Bruno Marchal wrote:

On 09 Dec 2017, at 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:
Similarly, a shroedinger car, once alive + dead, will never  
become a pure alive, or dead cat. It will only seems so for  
anyone looking at the cat, in the {alive, dead} base/apparatus.  
Superposition never disappear, and a coin moree or less with a  
precise position, is always a superposition of a coin with more  
or less precise momenta. The relation is given by the Fourier  
transforms, which gives the relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the  
uncertainty relations give uncertainties in positions and/or  
momentum far below any level of possible detection.


Of possible practical detection. That is good FAPP, but irrelevant  
for theoretical consideration.


This is a purely rhetorical objection, Bruno. And when you trot this  
out, as you do regularly, I know that your purpose is to obfuscate,  
and hide the fact that you have no rational argument to offer.


You confuse physics and metaphysics. The difference is not rhetorical,  
but fundamental in this thread.


Bruno





Bruce

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Re: Consistency of Postulates of QM

[Bruno Marchal]

On 10 Dec 2017, at 23:22, Brent Meeker wrote:




On 12/10/2017 7:37 AM, Bruno Marchal wrote:


On 09 Dec 2017, at 01:40, Brent Meeker wrote:




On 12/8/2017 4:27 PM, smitra wrote:

On 08-12-2017 01:46, Bruce Kellett wrote:

On 8/12/2017 11:43 am, smitra wrote:

On 08-12-2017 00:22, Bruce Kellett wrote:

On 8/12/2017 3:31 am, Bruno Marchal wrote:

On 06 Dec 2017, at 12:19, Bruce Kellett wrote:

But as I pointed out, thermal motion gives momenta of  
magnitudes such that the quantum uncertainties are  
negligible compared to the thermal randomness. And thermal  
motions are not coherent.


You seem to work in Bohr QM, with some dualism between the  
quantum reality and the classical reality.


Not at all. The (semi-)classical world emerges from the quantum
substrate; if you cannot give an account of this, then you  
have failed
to explain our everyday experience. And explaining that  
experience is

the purpose of physics.

You are right that this does not change anything FAPP, but  
our discussion is not about practical applications, but  
metaphysics.


No, we were talking about tossing a coin, we were not talking  
about
metaphysics. Your metaphysics has served merely to confuse you  
to the

extent that you do not understand even the simplest physics.



Andreas Albrecht  is not confused about anything,


How do you know?


and yet he agrees with Bruno on the point of coin tosses.


Argument from authority?



https://arxiv.org/abs/1212.0953

Page 4 section 4:

" The point here is that even with all our
simplifications, we have a plausibility argument that the
outcome of a coin flip is truly a quantum measurement
(really, a Schrödinger cat) and that the 50–50 outcome of
a coin toss may in principle be derived from the quantum
physics of a realistic coin toss with no reference to classical
notions of how we must “quantify our ignorance”."


Except that is inconsistent with the fact that stage magicians  
teach themselves to flip a coin and catch it with a predetermined  
result.


The fact that magicians have to learn to do that illustrates the  
hardness of that practice.


Showing that it is merely "hard" to violate quantum mechanics??

I doubt that they could do this for the protocol under  
consideration, where the coin is in a box, and we can shake it as  
long as we want.


I don't understand why it would be any different.  It's just more  
classical interactions.  Are you relying on sensitivity to initials  
conditions to split worlds?  Everett will turn over in his grave.


Agreed, but here it is the mixture of sensitivity to initials  
conditions (trace out to get my own relative state) + the quantum  
uncertainty.


Bruno



Brent

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Re: Consistency of Postulates of QM

[smitra]

On 10-12-2017 23:09, Brent Meeker wrote:

On 12/10/2017 4:42 AM, smitra wrote:

On 09-12-2017 21:18, Brent Meeker wrote:

On 12/9/2017 4:00 AM, smitra wrote:

On 09-12-2017 12:01, Bruce Kellett wrote:

On 9/12/2017 9:44 pm, smitra wrote:

On 09-12-2017 02:48, Bruce Kellett wrote:

On 9/12/2017 11:49 am, smitra wrote:

On 09-12-2017 00:03, Bruce Kellett wrote:

On 9/12/2017 4:21 am, Bruno Marchal wrote:

On 08 Dec 2017, at 00:22, Bruce Kellett wrote:

On 8/12/2017 3:31 am, Bruno Marchal wrote:

On 06 Dec 2017, at 12:19, Bruce Kellett wrote:

But as I pointed out, thermal motion gives momenta of 
magnitudes such that the quantum uncertainties are 
negligible compared to the thermal randomness. And thermal 
motions are not coherent.


You seem to work in Bohr QM, with some dualism between the 
quantum reality and the classical reality.


Not at all. The (semi-)classical world emerges from the 
quantum substrate; if you cannot give an account of this, 
then you have failed to explain our everyday experience. And 
explaining that experience is the purpose of physics.


No problem with this, except for your usual skepticism of 
Everett's program (say).


Skepticism is the scientific stance.



You are right that this does not change anything FAPP, but 
our discussion is not about practical applications, but 
metaphysics.


No, we were talking about tossing a coin, we were not talking 
about metaphysics. Your metaphysics has served merely to 
confuse you to the extent that you do not understand even the 
simplest physics.


That is ad hominem remark which I take as absence of argument.


You don't take kindly to criticism, do you Bruno?

All I said is that without collapse, shaking a box with some 
coin long enough would lead to the superposition of the two 
coin state. You seem to be the one confusing the local 
decoherence with some collapse. The Heisenberg uncertainties 
are great enough to amplify slight change of the move of the 
coin when bouncing on the wall.


That is simply assertion on your part, without a shred of 
argument or
justification. When one looks at the arguments, such as that 
put
forward by Albrecht and David (referred to by smitra), one 
finds that

the emperor has no clothes!

Similarly, a shroedinger car, once alive + dead, will never 
become a pure alive, or dead cat. It will only seems so for 
anyone looking at the cat, in the {alive, dead} 
base/apparatus. Superposition never disappear, and a coin 
moree or less with a precise position, is always a 
superposition of a coin with more or less precise momenta. The 
relation is given by the Fourier transforms, which gives the 
relative accessible states/worlds.


I pointed out that for a macroscopic object such as a coin, the
uncertainty relations give uncertainties in positions and/or 
momentum
far below any level of possible detection. And I gave an 
argument with
an actual calculation -- not just an assertion. Uncertainties 
in the
constituents of the object are uncorrelated, random, and cancel 
out.
So although the superposition originating from the big bang is 
intact
from the bird's point of view, it is so completely irrelevant 
for

everyday purposes that it is an insult to even refer to the
classicality of the world as FAPP -- it is complete. Relying on 
the
charge of "FAPP" as a justification for your assertions is 
nonsense.




It's not irrelevant if you don't have the information that 
locates you in a sector where the uncertainties are indeed small 
enough. You have to start with the complete state in the bird's 
view, and then consider the sector where you have some definite 
information and then project onto that subspace. If you do that, 
then your coins are not at all in a precisely enough classical 
state but rather in superpositions (entangled with the 
environment) that lead to wildly different outcomes of coin 
tosses.


E.g. in the bird's view there exists exact copies of me that 
live on planets that are not the same, some will have a radius 
of a few millimeter larger than others. Here exact copy means 
exactly the same conscious experience, which is then due to 
exactly the same computational state of the brain described by 
some bitstring that's exactly the same.


So, from totally different decoherent branches of the 
wavefunction one can factor out some bitstring describing a 
conscious experience, the reduced state of the rest of the 
universe in that sector is then a superposition of a many 
different effectively classical states.


If this were not true then each single conscious experience 
would contain in it information about such things as the exact  
number of atoms in the Earth, Sun etc. etc.


I prefer to live in the real world, so I would rather not indulge 
your

fantasies.

The real world is not what you think it is. It was only when you 
read about the fact that dinosaurs had once existed that the 
sector you were in diverged from other sectors where dinosaurs had 
never existed and some 

Re: Consistency of Postulates of QM

[smitra]

On 11-12-2017 03:08, Bruce Kellett wrote:

On 11/12/2017 12:21 pm, smitra wrote:

On 11-12-2017 00:55, Bruce Kellett wrote:


What you have to do if you want to claim that all chance outcomes are
of quantum origin is compare the relative magnitudes of quantum and
thermal fluctuations at room temperature -- room temperature because
that is where we do the experiments. And you haven't done that;
neither has Albrecht in the paper you reference. That is why his 
paper

is a load of nonsense.


Thermal fluctuations do not need to be eliminated, as they are of pure 
quantum mechanical origin. However, if one has to argue about that 
then one loses the point of the proposed experiment. At absolute zero 
the thermal fluctuations are due to zero point motion, take e.g. the 
harmonic oscillator which then has an energy of 1/2 hbar omega.


In generic non-integrable systems you'll have chaotic behavior where 
small perturbations grow exponentially.


Not necessarily. It depends on the relevant Lyapunov exponents. The
mean speed of molecules in a gas does not grow exponentially.



Typically the exponents are positive, there is a vast literature on this 
subject with some exactly solved cases, e.g. oddly shaped billiard 
balls.




Thermal fluctuations will then originate from quantum fluctuations.


Why then are thermal fluctuations temperature dependent? But be that
as it may, thermal fluctuations, and the random motions of molecules
in a gas, say, are not coherent, and there are no interference effects
between the molecules of a gas. Consequently, whatever their origin,
the motion is manifestly classical at room temperature.



Interference is a straw man. It's totally irrelevant whether or not some 
particular quantum aspects shows up in an experiment. Thing is that 
classical mechanics has already been falsified experimentally, so it's 
wrong to invoke a classical picture of what's going as a fundamental 
truth and put the burden of proof each time on a QM picture when it's 
not readily visible.


QM + decoherence only allows you to use classical reasoning to compute 
macroscopic observables with negligible errors, but this does not means 
that the macroscopic physical world is classical. It's just like the 
fact that GR reduces to classical mechanics, as far as the results of 
computations are concerned, but GR is still correct and the classical 
picture is still wrong no matter how weak the gravitational fields are.


Saibal

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Re: Equivalence Principle and Einstein Field Equations

[Russell Standish]

On Sun, Dec 10, 2017 at 07:06:00PM -0800, agrayson2...@gmail.com wrote:
> Excellent summary. TY. But why would Einstein think there could be a 
> covariant theory for accelerating frames when an observer inside such a 
> frame can do measurements to confirm acceleration and differences with 
> other such frames, unlike the case for inertial frames which are clearly 
> equivalent? AG 

If I have a tensor equation like C=\sum_{ij} A_{ij}B_{ij} where C is a
scalar quantity, then the coefficients of A and B must "covary" with
each other as you select different coordinate systems, since C must
remain unchanged regardless of coordinate system. Given the
setting is spacetime, that includes rotations in the time dimension
too, which is equivalent to changes in inertial reference frame by
velocity boost.

This is really obvious if we use things like the 4 dimensional dot
product, but traditional tensor equations are written in component
form, so one must ensure the covariance property is preserved to have
a valid equation. Indeed, in the above equation, superscripts are used
to represent the covariant indices, ie

  C = A_{ij}B^{ij}

where the summation sign is dropped, since it is obvious from the way
the equation is written.


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