Re: What are wavefunctions?

2014-02-05 Thread Bruno Marchal


On 05 Feb 2014, at 02:45, Russell Standish wrote:


On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote:
I did wonder once if, since the holographic principle implies that  
the
information in a universe is proportional to the surface area of  
the Hubble

sphere, could it be that the information in the *multiverse* is
proportional to the volume of the Hubble sphere?

(Although I guess the multiverse probably contains way more info than
that...)



Rather less, I would expect, for the reasons outlined in Theory of  
Nothing...


Yes rather less. It is the basic idea that taking everything is  
conceptually more simple than choosing anything among the everything.  
It is the main motivation for this list. Well, easier conceptually,  
but technically, this is only true up to be able to justify the white  
rabbits away, of course. I understand nothing only at that  
conceptual meta-level of 0-information theory, although it is more few- 
bits-information theory.


Bruno




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Re: What are wavefunctions?

2014-02-04 Thread Bruno Marchal


On 04 Feb 2014, at 07:16, meekerdb wrote:


On 2/3/2014 10:00 PM, Russell Standish wrote:

On Tue, Jan 07, 2014 at 12:44:57PM -0800, meekerdb wrote:

Layzer of course didn't know about the holographic principle, which
implies that the maximum possible entropy increases in proportion to
the surface area of the Hubble sphere rather than the volume.  Vic
Stenger has noted that if you assume the degrees of freedom for the
vacuum are proportional to this area (in Planck units) you get the
right order of magnitude for the energy density of the cosmological
constant.


Wow! That's quite something. Did Vic ever write this up somewhere?

Cheers



It's in section 12.2 of his 2011 book The Fallacy of Fine Tuning.



I appreciate that book, and basically everything Vic Stenger wrote on  
physics.
I am less enthusiast when he talk on God, despite I still agree with  
everything he says.
I don't believe in the God he is criticizing, nor on the need to  
advertise it in that way.


Bruno



Brent

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Re: What are wavefunctions?

2014-02-04 Thread meekerdb

On 2/3/2014 11:49 PM, LizR wrote:
I did wonder once if, since the holographic principle implies that the information in a 
universe is proportional to the surface area of the Hubble sphere, could it be that the 
information in the /multiverse/ is proportional to the volume of the Hubble sphere?


(Although I guess the multiverse probably contains way more info than that...)


But presumably only because it can have much bigger Hubble spheres. For a given size 
Hubble sphere, which is to say for a given epoch after the big bang, there are only 
finitely many different possible Hubble spheres.


At least that's the theory.

Brent

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Re: What are wavefunctions?

2014-02-04 Thread LizR
On 5 February 2014 06:24, meekerdb meeke...@verizon.net wrote:

  On 2/3/2014 11:49 PM, LizR wrote:

 I did wonder once if, since the holographic principle implies that the
 information in a universe is proportional to the surface area of the Hubble
 sphere, could it be that the information in the *multiverse* is
 proportional to the volume of the Hubble sphere?

  (Although I guess the multiverse probably contains way more info than
 that...)

  But presumably only because it can have much bigger Hubble spheres.  For
 a given size Hubble sphere, which is to say for a given epoch after the big
 bang, there are only finitely many different possible Hubble spheres.


Yes, I was only thinking of the subsection of the multiverse that includes
Hubble spheres of equal size to ours. Also I was only thinking of the
quantum multiverse, not the various alternatives. Given those constraints,
I wonder if the information content would come out proportional to the
volume? I guess if we assume space-time is quantised, then we can get a
maximum number of bits (maybe one per Planck volume?) - I suppose the
multiverse would then be every possible value that can occupy those
volumes. So say 2^N, where N=number of Planck volumes, which is around
10^180 according to a quick calculation, and assuming I haven't slipped up,
perish the thought. That doesn't seem right, though, because the Hubble
sphere isn't occupied anything like randomly, and presumably most
multiverse branches aren't either. I wonder how one could cut down the
number? Or if one should?

Any further thoughts on this?

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Re: What are wavefunctions?

2014-02-04 Thread Russell Standish
On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote:
 I did wonder once if, since the holographic principle implies that the
 information in a universe is proportional to the surface area of the Hubble
 sphere, could it be that the information in the *multiverse* is
 proportional to the volume of the Hubble sphere?
 
 (Although I guess the multiverse probably contains way more info than
 that...)
 

Rather less, I would expect, for the reasons outlined in Theory of Nothing...

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University of New South Wales  http://www.hpcoders.com.au


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Re: What are wavefunctions?

2014-02-04 Thread LizR
On 5 February 2014 14:45, Russell Standish li...@hpcoders.com.au wrote:

 On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote:
  I did wonder once if, since the holographic principle implies that the
  information in a universe is proportional to the surface area of the
 Hubble
  sphere, could it be that the information in the *multiverse* is
  proportional to the volume of the Hubble sphere?
 
  (Although I guess the multiverse probably contains way more info than
  that...)
 

 Rather less, I would expect, for the reasons outlined in Theory of
 Nothing...


Good point. In fact it presumably contains just enough information to
represent the laws of physics. However, although the information sums to
almost nothing, could there be some relation between the holographic
principle and the multiverse, possibly information-related, as suggested?

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Re: What are wavefunctions?

2014-02-04 Thread ghibbsa

On Wednesday, February 5, 2014 1:45:18 AM UTC, Russell Standish wrote:

 On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote: 
  I did wonder once if, since the holographic principle implies that the 
  information in a universe is proportional to the surface area of the 
 Hubble 
  sphere, could it be that the information in the *multiverse* is 
  proportional to the volume of the Hubble sphere? 
  
  (Although I guess the multiverse probably contains way more info than 
  that...) 
  

 Rather less, I would expect, for the reasons outlined in Theory of 
 Nothing... 

 
Is there a summary of ToN anywhere? 


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 Principal, High Performance Coders 
 Visiting Professor of Mathematics  hpc...@hpcoders.com.aujavascript: 
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Re: What are wavefunctions?

2014-02-04 Thread LizR
I don't know about a summary, but the whole book is available here:

http://www.hpcoders.com.au/theory-of-nothing.pdf


On 5 February 2014 17:58, ghib...@gmail.com wrote:


 On Wednesday, February 5, 2014 1:45:18 AM UTC, Russell Standish wrote:

 On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote:
  I did wonder once if, since the holographic principle implies that the
  information in a universe is proportional to the surface area of the
 Hubble
  sphere, could it be that the information in the *multiverse* is
  proportional to the volume of the Hubble sphere?
 
  (Although I guess the multiverse probably contains way more info than
  that...)
 

 Rather less, I would expect, for the reasons outlined in Theory of
 Nothing...


 Is there a summary of ToN anywhere?




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Re: What are wavefunctions?

2014-02-04 Thread Russell Standish
On Wed, Feb 05, 2014 at 06:42:14PM +1300, LizR wrote:
 I don't know about a summary, but the whole book is available here:
 
 http://www.hpcoders.com.au/theory-of-nothing.pdf
 

Thanks Liz. I should also add that I was alluding to the zero
information principle (Tegmark may call this the minimal information
principle, IIRC), which is really the subject of chapters 2  3 of my book.

Cheers

 
 On 5 February 2014 17:58, ghib...@gmail.com wrote:
 
 
  On Wednesday, February 5, 2014 1:45:18 AM UTC, Russell Standish wrote:
 
  On Tue, Feb 04, 2014 at 08:49:57PM +1300, LizR wrote:
   I did wonder once if, since the holographic principle implies that the
   information in a universe is proportional to the surface area of the
  Hubble
   sphere, could it be that the information in the *multiverse* is
   proportional to the volume of the Hubble sphere?
  
   (Although I guess the multiverse probably contains way more info than
   that...)
  
 
  Rather less, I would expect, for the reasons outlined in Theory of
  Nothing...
 
 
  Is there a summary of ToN anywhere?
 
 
 
 
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Re: What are wavefunctions?

2014-02-03 Thread Russell Standish
On Tue, Jan 07, 2014 at 12:44:57PM -0800, meekerdb wrote:
 
 Layzer of course didn't know about the holographic principle, which
 implies that the maximum possible entropy increases in proportion to
 the surface area of the Hubble sphere rather than the volume.  Vic
 Stenger has noted that if you assume the degrees of freedom for the
 vacuum are proportional to this area (in Planck units) you get the
 right order of magnitude for the energy density of the cosmological
 constant.
 

Wow! That's quite something. Did Vic ever write this up somewhere?

Cheers

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Principal, High Performance Coders
Visiting Professor of Mathematics  hpco...@hpcoders.com.au
University of New South Wales  http://www.hpcoders.com.au


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Re: What are wavefunctions?

2014-02-03 Thread meekerdb

On 2/3/2014 10:00 PM, Russell Standish wrote:

On Tue, Jan 07, 2014 at 12:44:57PM -0800, meekerdb wrote:

Layzer of course didn't know about the holographic principle, which
implies that the maximum possible entropy increases in proportion to
the surface area of the Hubble sphere rather than the volume.  Vic
Stenger has noted that if you assume the degrees of freedom for the
vacuum are proportional to this area (in Planck units) you get the
right order of magnitude for the energy density of the cosmological
constant.


Wow! That's quite something. Did Vic ever write this up somewhere?

Cheers



It's in section 12.2 of his 2011 book The Fallacy of Fine Tuning.

Brent

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Re: What are wavefunctions?

2014-02-03 Thread Russell Standish
On Mon, Feb 03, 2014 at 10:16:15PM -0800, meekerdb wrote:
 On 2/3/2014 10:00 PM, Russell Standish wrote:
 On Tue, Jan 07, 2014 at 12:44:57PM -0800, meekerdb wrote:
 Layzer of course didn't know about the holographic principle, which
 implies that the maximum possible entropy increases in proportion to
 the surface area of the Hubble sphere rather than the volume.  Vic
 Stenger has noted that if you assume the degrees of freedom for the
 vacuum are proportional to this area (in Planck units) you get the
 right order of magnitude for the energy density of the cosmological
 constant.
 
 Wow! That's quite something. Did Vic ever write this up somewhere?
 
 Cheers
 
 
 It's in section 12.2 of his 2011 book The Fallacy of Fine Tuning.
 
 Brent
 

Not in a peer reviewed article, then. Mind you I don't blame him,
given the current state of peer review.

I'm unfortunately not sufficiently interested to buy the book, nor is
it available in my uni's library :(. I'll have to leave this on my
toread list.

Cheers

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Principal, High Performance Coders
Visiting Professor of Mathematics  hpco...@hpcoders.com.au
University of New South Wales  http://www.hpcoders.com.au


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Re: What are wavefunctions?

2014-02-03 Thread meekerdb

On 2/3/2014 11:14 PM, Russell Standish wrote:

On Mon, Feb 03, 2014 at 10:16:15PM -0800, meekerdb wrote:

On 2/3/2014 10:00 PM, Russell Standish wrote:

On Tue, Jan 07, 2014 at 12:44:57PM -0800, meekerdb wrote:

Layzer of course didn't know about the holographic principle, which
implies that the maximum possible entropy increases in proportion to
the surface area of the Hubble sphere rather than the volume.  Vic
Stenger has noted that if you assume the degrees of freedom for the
vacuum are proportional to this area (in Planck units) you get the
right order of magnitude for the energy density of the cosmological
constant.


Wow! That's quite something. Did Vic ever write this up somewhere?

Cheers


It's in section 12.2 of his 2011 book The Fallacy of Fine Tuning.

Brent


Not in a peer reviewed article, then. Mind you I don't blame him,
given the current state of peer review.

I'm unfortunately not sufficiently interested to buy the book, nor is
it available in my uni's library :(. I'll have to leave this on my
toread list.


He also mentions it here

http://www.colorado.edu/philosophy/vstenger/BookChapters/OxNoEv13.pdf

on pg 53, but without a calculation (which is very short anyway).

Brent



Cheers



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Re: What are wavefunctions?

2014-02-03 Thread LizR
I did wonder once if, since the holographic principle implies that the
information in a universe is proportional to the surface area of the Hubble
sphere, could it be that the information in the *multiverse* is
proportional to the volume of the Hubble sphere?

(Although I guess the multiverse probably contains way more info than
that...)

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Re: What are wavefunctions?

2014-01-17 Thread Bruno Marchal


On 16 Jan 2014, at 18:53, meekerdb wrote:


On 1/15/2014 11:42 PM, Jason Resch wrote:




On Thu, Jan 16, 2014 at 12:58 AM, meekerdb meeke...@verizon.net  
wrote:

On 1/15/2014 7:05 PM, Jason Resch wrote:
Hyper determinism makes little sense as a serious theory to me.  
Why should particle properties conform to what a computer's random  
number generator outputs, and then the digits of Pi, and then the  
binary expansion of the square root of 2, all variously as the  
experimenters change the knobs as to what determines the spin axis  
of the lepton their analyzer measures. Are radioactive decays of  
particles really such things that are governed by the behavior of  
a selected random source, or alternately, are they really such  
things that govern what the digits of Pi or the square root of 2  
are?


They are all part of the same reality.

Are they? Aren't numbers like Pi and sqrt(2) beyond the reality of  
QM, or rather, more fundamental than it? The moment you admit  
numbers like Pi into your reality, you get much more than just QM.


Of course QM is just a model


A theory.


of how we think the world works...like arithmetic is a model of  
countable things.  Neither one is *reality*.


PA is a reality, by itself, indeed an existing Löbian machine, and PA  
talks about a reality which is vaster than PA, and that no machine can  
grasp in its entirety. You confuse theory and model here.







You assume its the experimental choice of measurement that  
determines the particles response, but I think the picture is  
supposed to be that both the particle in the experiment and the  
particles making up the experimenter are determined by the same laws.


So how, when using the digits of Pi to decide whether to measure  
the x-axis, or the y-axis, does the particle (when it decays), know  
to have both electron and positron agree measured on some axis,  
when that axis is determined by some relation between a circle and  
its diameter? Here the laws involved seemed to go beyond physical  
laws, it introduces mathematical laws, which can selectively be  
made to control/guide physics..


They only 'seem to' because you neglect the fact that in the  
experiment you don't use the digits of pi from Platonia, you use  
their physical instantiation as calculated in the registers of a  
computer or written ink on a page.


You agree that there is a difference between Platonia, and the inside  
more terrestrial perception of it.


Bruno





Brent

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Re: What are wavefunctions?

2014-01-17 Thread Bruno Marchal


On 16 Jan 2014, at 22:31, LizR wrote:

Everything else I've said on this subject has been in response to  
people trying to argue that physics is not time symmetric. So far  
all such arguments have been a variant on the second law says so  
and my response has been a variant on the second law emerges above  
the level at which we can detect time symmetry. (Plus I've invoked  
boundary conditions on the universe to explain how the second law  
can arise from time symmetric physics...)



I agree a priori with you on this.
I can agree also that this time-symmetry (of QM, which time  
symmetrical) + boundary special condition can be consistent with QM +  
one reality (although weird and not satisfying)


I think pure QM (without boundary condition, that is MW) is even more  
symmetrical, and conceptually more simple, and that your point go  
through it.


The boundary condition a still a way to select a dream as more real  
than other dream, and of course, does or make sense in comp, unless  
the numbers conspire in making the whole geography into physics which  
is not reasonable.


Bruno

http://iridia.ulb.ac.be/~marchal/



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Re: What are wavefunctions?

2014-01-17 Thread meekerdb

On 1/17/2014 2:18 AM, Bruno Marchal wrote:


PA is a reality, by itself, indeed an existing Löbian machine, and PA talks about a 
reality which is vaster than PA, and that no machine can grasp in its entirety. You 
confuse theory and model here.


You can't kick Peano's axioms.

Brent

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Re: What are wavefunctions?

2014-01-17 Thread Jason Resch



On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net wrote:


On 1/17/2014 2:18 AM, Bruno Marchal wrote:


PA is a reality, by itself, indeed an existing Löbian machine, and 
 PA talks about a reality which is vaster than PA, and that no mac 
hine can grasp in its entirety. You confuse theory and model here.


You can't kick Peano's axioms.


What is your point? That things don't exist unless you can kick them?

Jason




Brent
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Re: What are wavefunctions?

2014-01-17 Thread LizR
On 18 January 2014 16:08, Jason Resch jasonre...@gmail.com wrote:

 On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net wrote:

 On 1/17/2014 2:18 AM, Bruno Marchal wrote:

 PA is a reality, by itself, indeed an existing Löbian machine, and PA
 talks about a reality which is vaster than PA, and that no machine can
 grasp in its entirety. You confuse theory and model here.

 You can't kick Peano's axioms.

 What is your point? That things don't exist unless you can kick them?


Real things kick back. Maths kicks back...

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Re: What are wavefunctions?

2014-01-17 Thread meekerdb

On 1/17/2014 7:34 PM, LizR wrote:
On 18 January 2014 16:08, Jason Resch jasonre...@gmail.com 
mailto:jasonre...@gmail.com wrote:


On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net
mailto:meeke...@verizon.net wrote:

On 1/17/2014 2:18 AM, Bruno Marchal wrote:

PA is a reality, by itself, indeed an existing Löbian machine, and PA talks 
about
a reality which is vaster than PA, and that no machine can grasp in its 
entirety.
You confuse theory and model here.

You can't kick Peano's axioms.

What is your point? That things don't exist unless you can kick them?


Real things kick back. Maths kicks back...


Only metaphorically.

Brent

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Re: What are wavefunctions?

2014-01-17 Thread LizR
On 18 January 2014 18:50, meekerdb meeke...@verizon.net wrote:

  On 1/17/2014 7:34 PM, LizR wrote:

  On 18 January 2014 16:08, Jason Resch jasonre...@gmail.com wrote:

  On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net wrote:

  On 1/17/2014 2:18 AM, Bruno Marchal wrote:

 PA is a reality, by itself, indeed an existing Löbian machine, and PA
 talks about a reality which is vaster than PA, and that no machine can
 grasp in its entirety. You confuse theory and model here.

 You can't kick Peano's axioms.

  What is your point? That things don't exist unless you can kick them?


  Real things kick back. Maths kicks back...

 Only metaphorically.


Fairly obviously.

(I refute it thus! said Samuel Johnson, stubbing his toe against the
irrationality of pi.)

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Re: What are wavefunctions?

2014-01-17 Thread Jason Resch
On Fri, Jan 17, 2014 at 11:50 PM, meekerdb meeke...@verizon.net wrote:

  On 1/17/2014 7:34 PM, LizR wrote:

  On 18 January 2014 16:08, Jason Resch jasonre...@gmail.com wrote:

  On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net wrote:

  On 1/17/2014 2:18 AM, Bruno Marchal wrote:

 PA is a reality, by itself, indeed an existing Löbian machine, and PA
 talks about a reality which is vaster than PA, and that no machine can
 grasp in its entirety. You confuse theory and model here.

 You can't kick Peano's axioms.

  What is your point? That things don't exist unless you can kick them?


  Real things kick back. Maths kicks back...


 Only metaphorically.


The laws of physics prevent you from traveling at a speed more than
~300,000,000 m/s. The laws of arithmetic prevent you from writing down more
than 2 distinct factors of 17. They seem equally forceful, each in their
own way. The laws of mathematics may be even more forceful, for it is
conceivable in some physical universe you can go faster than the speed of
light in this universe, it is much harder to conceive of a universe where
you could write down a third factor of 17.

Jason

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Re: What are wavefunctions?

2014-01-17 Thread meekerdb

On 1/17/2014 10:16 PM, Jason Resch wrote:




On Fri, Jan 17, 2014 at 11:50 PM, meekerdb meeke...@verizon.net 
mailto:meeke...@verizon.net wrote:


On 1/17/2014 7:34 PM, LizR wrote:

On 18 January 2014 16:08, Jason Resch jasonre...@gmail.com
mailto:jasonre...@gmail.com wrote:

On Jan 17, 2014, at 6:58 PM, meekerdb meeke...@verizon.net
mailto:meeke...@verizon.net wrote:

On 1/17/2014 2:18 AM, Bruno Marchal wrote:

PA is a reality, by itself, indeed an existing Löbian machine, and PA 
talks
about a reality which is vaster than PA, and that no machine can grasp 
in its
entirety. You confuse theory and model here.

You can't kick Peano's axioms.

What is your point? That things don't exist unless you can kick them?


Real things kick back. Maths kicks back...


Only metaphorically.


The laws of physics prevent you from traveling at a speed more than 
~300,000,000 m/s.


A curious choice.  The 'laws of physics' say light travels the same speed in vacuo in all 
frames.  The number 299,792,458 is just an arbitrary conversion factor between meters and 
seconds.




The laws of arithmetic prevent you from writing down more than 2 distinct 
factors of 17.


  17 = (17/4)*4

I've got a million of'em.

Brent

They seem equally forceful, each in their own way. The laws of mathematics may be even 
more forceful, for it is conceivable in some physical universe you can go faster than 
the speed of light in this universe, it is much harder to conceive of a universe where 
you could write down a third factor of 17.







Jason
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Re: What are wavefunctions?

2014-01-17 Thread LizR
On 18 January 2014 19:45, meekerdb meeke...@verizon.net wrote:

  On 1/17/2014 10:16 PM, Jason Resch wrote:

 The laws of arithmetic prevent you from writing down more than 2 distinct
 factors of 17.

   17 = (17/4)*4

 I've got a million of'em.


... using integers, which we know were created by God, rather than man-made
fractions :-)

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Re: What are wavefunctions?

2014-01-16 Thread Bruno Marchal


On 15 Jan 2014, at 21:11, meekerdb wrote:


On 1/15/2014 4:13 AM, Bruno Marchal wrote:
I am not convinced, as I tend to not believe in any primitive time  
and space, at least when I tend to believe in comp (of course I  
*know* nothing).


QM is indeed reversible (in large part), but using this to select  
one branch by boundary condition, is still like a form of cosmic  
solipsism to me. We can't refute it, and unlike most QM collapse  
theories, we can't criticize it from locality and determinacy, but  
that does not yet make it convincing compare to MW, and infinitely  
more so in the comp frame, where we can't avoid the many dreams.


It's just information from the future - which is exactly the same  
thing as true randomness, and both are operationally the same as  
FPI.  That's why I think an advancement in QM interpretation would  
be to derive probability.  Comp provides an explanation of  
randomness, but it's not clear to me that it implies a complex  
Hilbert space.


It should, but even the orthomodularity quantum tatutology is still  
non tractable.
So it not *yet* clear, but that question has been reformulated in  
purely arithmetical terms. The arithmetical quantization []p (with p  
sigma_1, and []p = Bp  Dp  p, for example. B = Gödel's beweisbar)  
dtermine the answer, alas, still unknown.


Bruno.





Brent

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http://iridia.ulb.ac.be/~marchal/



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Re: What are wavefunctions?

2014-01-16 Thread LizR
On 16 January 2014 20:00, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 7:08 PM, LizR wrote:

  On 16 January 2014 14:11, meekerdb meeke...@verizon.net wrote:


  You can do that (in fact it may have been done).  You have two emitters
 with polarizers and a detector at which you post-select only those
 particles that arrive and form a singlet.  Then you will find that the
 correlation counts for that subset violates Bell's inequality for polarizer
 settings of 30, 60, 120deg.

  I assume that means Price's (and Bell's) assumption that violations of
 Bell's inequality can be explained locally and realistically with time
 symmetry is definitely wrong...?


 ?? Why do you conclude that?  It's the time-reverse of the EPR that
 violated BI.

 Because as I (perhaps mis-) understand it, Price claims that we need to
take both past AND future boundary conditions into account to explain EPR
with time symmetry. If we can explain it with only a forward in time or
backward in time explanation, then we aren't using both.

Or I may be missing the point. That often happens. Now that I think about
it, I probably am. I shall go into the garden and eat worms, and while I
tuck in maybe you could explain to me whether I jumped to completely the
wrong conclusion.

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Re: What are wavefunctions?

2014-01-16 Thread Bruno Marchal


On 16 Jan 2014, at 01:57, meekerdb wrote:


On 1/15/2014 4:03 PM, LizR wrote:
By the way, I may have this wrong but it seems to me your  
hyperdeterminism objection is an objection to block universes  
generally. I can't see how the big crunch (or timelike infinity)  
being a boundary condition on the universe is a problem in a block  
universe (or multiverse) ...?


I think Bruno is thinking of a tree-like branching block  
multiverse so there can still be FPI due to the branches.


yes, like in arithmetic.


Otherwise definite, random things have to happen in realizing the  
block universe - and Bruno hates random things and he likes  
infinities,


Well, let us say that I hate only the *assumption* of 3p randomness.  
Einstein define insanity by such belief (of course that is not an  
argument).




so...  But you should read L.S. Schulman's solution to the problem  
of randomness.  He speculates that within the domain of a state we  
can prepare, which is of measure hbar=/=0, there are special states  
which are causally connected to *future* states and when we choose a  
measurement in the future we are selecting out one of these special  
states.



Is that not already the case in the WM duplication experiment? The  
problem is not in the selection, but in a physical mechanism making  
disappear the realities not selected. They always need to add  
something to the equation, be it a guiding potential, boundary  
conditions, etc.





Brent

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http://iridia.ulb.ac.be/~marchal/



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Re: What are wavefunctions?

2014-01-16 Thread Bruno Marchal


On 16 Jan 2014, at 04:05, Jason Resch wrote:

Hyper determinism makes little sense as a serious theory to me. Why  
should particle properties conform to what a computer's random  
number generator outputs, and then the digits of Pi, and then the  
binary expansion of the square root of 2, all variously as the  
experimenters change the knobs as to what determines the spin axis  
of the lepton their analyzer measures. Are radioactive decays of  
particles really such things that are governed by the behavior of a  
selected random source, or alternately, are they really such things  
that govern what the digits of Pi or the square root of 2 are?


Yes, that's my point. Price make a logical point, though. But we have  
to abandon QM for QM + a lot of extra-information to select one reality.


In that case why not come back to Ptolemeaus. The idea that it is the  
sun which moves in the sky is consistent too, even with Newton  
physics, if you put enough extra-data in the theory.


With one reality, a quantum computer works only because of extra- 
magical boundary conditions.


Bruno




Jason


On Wed, Jan 15, 2014 at 6:13 AM, Bruno Marchal marc...@ulb.ac.be  
wrote:


On 15 Jan 2014, at 11:10, LizR wrote:


On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:

On 14 Jan 2014, at 22:04, LizR wrote:

Sorry, I realise that last sentence could be misconstrued by  
someone who's being very nitpicky and looking for irrelevant  
loopholes to argue about, so let's try again.


Now how about discussing what I've actually claimed, that the time  
symmetry of fundamental physics could account for the results  
obtained in EPR experiments?


Logically, yes.

But you need hyper-determinism, that is you need to select very  
special boundary conditions, which makes Cramer's transaction  
theory close to Bohm's theory.


I'm not sure what you mean by special boundary conditions. The bcs  
in an Aspect type experiment are the device which creates the  
photons, and the settings of the measuring apparatuses.


The setting of the analyser must be predetermined. And not in the  
mechanist sense, where the choice of the analyser is still made by  
you, even if deterministically so. With only one branch, you are not  
just using irreversibility, but you are using the boundary condition  
selecting a branch among all in the universal wave.





These are special but only in that the photons are entangled ...  
note that this isn't Cramer's or Bohm's theory (the transaction  
theory requires far more complexity that this).


Those are still many-world theories, + some ugly selection  
principle to get one branch. It is very not natural, as you have  
quasi microsuperposition (appearance of many branches), but the  
macro-one are eliminated by ad hoc boundary conditions, which will  
differ depending on where you will decide to introduce the  
Heisenberg cut. Also, QM will prevent us to know or measure those  
boundary conditions, which makes them into (local, perhaps, in  
*some* sense) hidden variable theory.


I don't understand the above. The theory is simply QM with no  
collapse and with no preferred time direction (it assumes any  
system which violates Bell's inequality has to operate below the  
level where decoherence brings in the effects of the entropy  
gradient). It is both local and realistic, since time symmetry is  
Bell's 4th assumption - it allows EPR experiments to be local and  
realistic (I am relying on John Bell for this information, I  
wouldn't be able to work it out myself). So it definitely is a  
hidden variable theory.


Yes, and I am willing to accept it is local. but it is hyper- 
determined. It means that if I chose the setting of the two  
analyser in the Aspect experience by looking at my horoscope, that  
horoscope was determined by the whole future of the phsyical  
universe. Logically possible, you are right, but ugly, as it is a  
selection principle based on boundary conditions. It is more local  
than Bohm, and it does not need a new potential, but it is sill  
using abnormal special data for the TOE. It is no more a nice and  
gentle equation like the SWE, but that same equation together with  
tuns of mega-terra-gigabyte of data.





I think for it to work the system is kept from undergoing  
decoherence or any interaction that would lead to MWI branching.  
EPR experiments only appear to work for systems that are shielded  
from such effects, I think? So there isn't a problem with the MWI -  
the whole thing takes place in one branch, with no quantum  
interfence etc being relevant. (I believe that EPR experiments lose  
their ability to violate Bell's inequality once interactions occur  
that could cause MWI branching within the system under  
consideration???)


?





Many worlds is far less ad-hoc, imo. There is no Heisenberg cut,  
and the boundary conditions does not play any special role, and  
indeed they are all realized in the universal wave (and in  

Re: What are wavefunctions?

2014-01-16 Thread John Clark
On Tue, Jan 14, 2014 at 2:09 PM, meekerdb meeke...@verizon.net wrote:

  It [entropy] is NOT the log of the number of ways a macro-state could
 form.  That would be ambiguous in any case (do different order of events
 count as different ways?


Yes obviously.

 the Boltzmann formula shows the relationship between entropy and the
 number of ways system can be arranged


Most experts say there is only one way a Black Hole can be arranged because
it has no parts, or if it does the experts can't agree on exactly what
those parts are, see Susskind's The Black Hole Wars. So for now it's best
to say entropy is the logarithm of the ways it could have been made.

 To say it only has mass, charge, and angular momentum is just to give a
 classical macro-state description


It's the best we can do. Perhaps when we find a quantum theory of gravity
we can say more, but not now.

 John k Clark

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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/15/2014 11:42 PM, Jason Resch wrote:




On Thu, Jan 16, 2014 at 12:58 AM, meekerdb meeke...@verizon.net 
mailto:meeke...@verizon.net wrote:


On 1/15/2014 7:05 PM, Jason Resch wrote:

Hyper determinism makes little sense as a serious theory to me. Why should 
particle
properties conform to what a computer's random number generator outputs, 
and then
the digits of Pi, and then the binary expansion of the square root of 2, all
variously as the experimenters change the knobs as to what determines the 
spin axis
of the lepton their analyzer measures. Are radioactive decays of particles 
really
such things that are governed by the behavior of a selected random source, 
or
alternately, are they really such things that govern what the digits of Pi 
or the
square root of 2 are?


They are all part of the same reality.


Are they? Aren't numbers like Pi and sqrt(2) beyond the reality of QM, or rather, more 
fundamental than it? The moment you admit numbers like Pi into your reality, you get 
much more than just QM.


Of course QM is just a model of how we think the world works...like arithmetic is a model 
of countable things.  Neither one is *reality*.



You assume its the experimental choice of measurement that determines the 
particles
response, but I think the picture is supposed to be that both the particle 
in the
experiment and the particles making up the experimenter are determined by 
the same laws.


So how, when using the digits of Pi to decide whether to measure the x-axis, or the 
y-axis, does the particle (when it decays), know to have both electron and positron 
agree measured on some axis, when that axis is determined by some relation between a 
circle and its diameter? Here the laws involved seemed to go beyond physical laws, it 
introduces mathematical laws, which can selectively be made to control/guide physics..


They only 'seem to' because you neglect the fact that in the experiment you don't use the 
digits of pi from Platonia, you use their physical instantiation as calculated in the 
registers of a computer or written ink on a page.


Brent

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Re: What are wavefunctions?

2014-01-16 Thread Jason Resch
On Thu, Jan 16, 2014 at 11:53 AM, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 11:42 PM, Jason Resch wrote:




 On Thu, Jan 16, 2014 at 12:58 AM, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 7:05 PM, Jason Resch wrote:

 Hyper determinism makes little sense as a serious theory to me. Why
 should particle properties conform to what a computer's random number
 generator outputs, and then the digits of Pi, and then the binary expansion
 of the square root of 2, all variously as the experimenters change the
 knobs as to what determines the spin axis of the lepton their analyzer
 measures. Are radioactive decays of particles really such things that are
 governed by the behavior of a selected random source, or alternately, are
 they really such things that govern what the digits of Pi or the square
 root of 2 are?


  They are all part of the same reality.


  Are they? Aren't numbers like Pi and sqrt(2) beyond the reality of QM,
 or rather, more fundamental than it? The moment you admit numbers like Pi
 into your reality, you get much more than just QM.


 Of course QM is just a model of how we think the world works...like
 arithmetic is a model of countable things.  Neither one is *reality*.




 You assume its the experimental choice of measurement that determines the
 particles response, but I think the picture is supposed to be that both the
 particle in the experiment and the particles making up the experimenter are
 determined by the same laws.


  So how, when using the digits of Pi to decide whether to measure the
 x-axis, or the y-axis, does the particle (when it decays), know to have
 both electron and positron agree measured on some axis, when that axis is
 determined by some relation between a circle and its diameter? Here the
 laws involved seemed to go beyond physical laws, it introduces
 mathematical laws, which can selectively be made to control/guide
 physics..


 They only 'seem to' because you neglect the fact that in the experiment
 you don't use the digits of pi from Platonia, you use their physical
 instantiation as calculated in the registers of a computer or written ink
 on a page.


And what is the physical link between the computer's registers and the
radioactive decay? What keeps it from breaking down in the next moment?

If all that information has to be assumed at the start, there's no reason
an equally big description would be any less likely, and thus there is no
reason it shouldn't diverge from our expectations in the next second.


(Also, I would say they do come from Platonia, in that the platonic
properties of Pi (which the computer is inspecting and reporting) prevents
the computer from outputting the digits of some other number. Consider that
the numbers of Pi go on forever and have an infinite expansion, but there
is no physical way to realize that expansion. In that sense, the digits of
Pi transcends our own physics and must be outside/beyond it.)

Jason

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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/16/2014 1:48 AM, LizR wrote:
On 16 January 2014 20:00, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net 
wrote:


On 1/15/2014 7:08 PM, LizR wrote:

On 16 January 2014 14:11, meekerdb meeke...@verizon.net
mailto:meeke...@verizon.net wrote:


You can do that (in fact it may have been done).  You have two emitters 
with
polarizers and a detector at which you post-select only those particles 
that
arrive and form a singlet.  Then you will find that the correlation 
counts for
that subset violates Bell's inequality for polarizer settings of 30, 
60, 120deg.

I assume that means Price's (and Bell's) assumption that violations of 
Bell's
inequality can be explained locally and realistically with time symmetry is
definitely wrong...?


?? Why do you conclude that?  It's the time-reverse of the EPR that 
violated BI.

Because as I (perhaps mis-) understand it, Price claims that we need to take both past 
AND future boundary conditions into account to explain EPR with time symmetry. If we can 
explain it with only a forward in time or backward in time explanation, then we aren't 
using both.


But in the reverse EPR we are in effect using both past and future boundary conditions.  
At the emitters we set the polarizers - that's the past boundary condition.  At the single 
detector we post-select only those incoming pairs that form a net-zero spin; so that's a 
future boundary condition.


This is only a 'thought experiment' because I don't think there's any practical way to 
capture and test pairs for net-zero spin.  Note that you must NOT measure the spins, you 
have to select the net-zero pair without measuring either one.


Brent



Or I may be missing the point. That often happens. Now that I think about it, I probably 
am. I shall go into the garden and eat worms, and while I tuck in maybe you could 
explain to me whether I jumped to completely the wrong conclusion.



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Re: What are wavefunctions?

2014-01-16 Thread LizR
On 17 January 2014 07:56, meekerdb meeke...@verizon.net wrote:

  On 1/16/2014 1:48 AM, LizR wrote:

  On 16 January 2014 20:00, meekerdb meeke...@verizon.net wrote:

   On 1/15/2014 7:08 PM, LizR wrote:

  On 16 January 2014 14:11, meekerdb meeke...@verizon.net wrote:


  You can do that (in fact it may have been done).  You have two
 emitters with polarizers and a detector at which you post-select only those
 particles that arrive and form a singlet.  Then you will find that the
 correlation counts for that subset violates Bell's inequality for polarizer
 settings of 30, 60, 120deg.

  I assume that means Price's (and Bell's) assumption that violations of
 Bell's inequality can be explained locally and realistically with time
 symmetry is definitely wrong...?


  ?? Why do you conclude that?  It's the time-reverse of the EPR that
 violated BI.

  Because as I (perhaps mis-) understand it, Price claims that we need to
 take both past AND future boundary conditions into account to explain EPR
 with time symmetry. If we can explain it with only a forward in time or
 backward in time explanation, then we aren't using both.


 But in the reverse EPR we are in effect using both past and future
 boundary conditions.  At the emitters we set the polarizers - that's the
 past boundary condition.  At the single detector we post-select only those
 incoming pairs that form a net-zero spin; so that's a future boundary
 condition.


I must admit I thought you were saying we could do it using ONLY the future
boundary conditions. If you use both then you should logically use both in
the forwards case, too, so I assume Price's explanation still stands.




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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/16/2014 4:02 AM, Bruno Marchal wrote:
Yes, that's my point. Price make a logical point, though. But we have to abandon QM for 
QM + a lot of extra-information to select one reality.


In that case why not come back to Ptolemeaus. The idea that it is the sun which moves in 
the sky is consistent too, even with Newton physics, if you put enough extra-data in the 
theory.


It's not only consistent it is so in the frame used when modeling the galaxy. Because the 
physics is invariant under various transforms one always transforms so as to make the 
problem easier.


Brent

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Re: What are wavefunctions?

2014-01-16 Thread Jesse Mazer
On Wed, Jan 15, 2014 at 7:08 PM, LizR lizj...@gmail.com wrote:

 On 16 January 2014 03:51, Jesse Mazer laserma...@gmail.com wrote:


 On Wed, Jan 15, 2014 at 5:10 AM, LizR lizj...@gmail.com wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very
 special boundary conditions, which makes Cramer's transaction theory close
 to Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses. These are special but only in that
 the photons are entangled ... note that this isn't Cramer's or Bohm's
 theory (the transaction theory requires far more complexity that this).



 Time symmetry in the laws of physics alone, without any special
 restriction on boundary conditions, can't get you violation of Bell
 inequalities. Ordinary time symmetry doesn't mean you have to take into
 account both future and past to determine what happens in a given region of
 spacetime after all, it just means you can deduce it equally well going in
 *either* direction. So in a deterministic time-symmetric theory (Price's
 speculations about hidden variables are at least compatible with
 determinism) it's still true that what happens in any region of spacetime
 can be determined entirely by events in its past light cone, say the ones
 occurring at some arbitrarily-chosen initial tim. This means that in a
 Price-like theory where measurement results are explained in terms of
 hidden variables the particles carry with them from emitter to
 experimenters, it must be true that the original assignment of the hidden
 variables to each particle at the emitter is determined by the past light
 cone of the event of each particle leaving the emitter. Meanwhile, the
 event of an experimenter choosing which measurement to perform will have
 its own past light cone, and there are plenty of events in the past light
 cone of the choice that do *not* lie in the past light cone of the
 particles leaving the emitter.

 So, without any restriction on boundary conditions, one can choose an
 ensemble of possible initial conditions with the following properties:

 1. The initial states of all points in space that line in the past light
 cone of the particles leaving the emitter are identical for each member of
 the ensemble, so in every possible history generated from these initial
 conditions, the particles have the same hidden variables associated with
 them.

 2. The initial states of points in space that lie in the past light cone
 of the experimenters choosing what spin direction to measure vary in
 different members of the ensemble, in such a way that all combinations of
 measurement choices are represented in different histories chosen from this
 ensemble.

 If both these conditions apply, Bell's proofs that various inequalities
 shouldn't be violated works just fine--for example, there's no combination
 of hidden variables you can choose for the particle pair that ensure that
 in all the histories where the experimenters measure along the *same* axis
 they get opposite results (spin-up for one experimenter, spin-down for the
 other) with probability 1, but in all the histories where they measure
 along two *different* axes they have less than a 1/3 chance of getting
 opposite results. Only by having the hidden variables assigned during
 emission be statistically correlated to the choices the experimenters later
 make about measurements can Price's argument work, and the argument above
 shows that time-symmetry without special boundary conditions won't suffice
 for this.

 If you're right then Price is wrong. However I don't recall him saying
 that the only consequence of time symmetry is that events can be, so to
 speak, worked backwards equally well. In particular, I read his EPR
 explanation as showing that both future and past boundary conditions were
 relevant in explaining the violations of B's Inequality. The
 forwards-and-backwards version would prevent time symmetry having any
 detectable effects, as far as I can see. (Also I'd like to see an
 explanation of EPR which works backwards from the measurement settings to
 the emitter and explains the violation of B's Inequality. That would
 definitely be a clincher!)



I don't think my argument necessarily conflicts with Price, since I don't
remember him clearly saying that the Bell inequality violations could be
resolved without time-symmetric boundary conditions alongside
time-symmetric 

Re: What are wavefunctions?

2014-01-16 Thread LizR
On 17 January 2014 08:40, Jesse Mazer laserma...@gmail.com wrote:

 On Wed, Jan 15, 2014 at 7:08 PM, LizR lizj...@gmail.com wrote:

 On 16 January 2014 03:51, Jesse Mazer laserma...@gmail.com wrote:

 (SNIP)
 Still, the fact remains that if your local realistic time-symmetric
 theory of physics *is* a dynamical one where later conditions can be
 derived from initial conditions, then the argument I made in the previous
 comment you quoted should still apply, and in that case time-symmetry
 without very specially-chosen initial boundary conditions will be of no
 help in explaining how Bell's inequality can be violated. So it's not
 correct to just say that Bell assumed time was asymmetric, and thus that
 the type of time-symmetry we see in *existing* theories of physics like
 quantum field theory is enough to discount his proof. In terms of a Venn
 diagram, there would be an overlap between the circle time-symmetric (or
 CPT-symmetric) local realistic theories and theories that satisfy the
 assumptions of Bell's proof, and all existing time-symmetric theories
 (except for general relativity in non-globally-hyperbolic spacetimes) would
 fall into that overlap region. Price may be correct that the general *idea*
 of time-symmetry points to a possible loophole in Bell's proof, but taking
 advantage of this loophole would require a new and different type of
 time-symmetric theory from the ones physicists have used in the past to
 model real-world situations.


I don't *think* Price is thinking of a dynamical theory (assuming I've
understood you correctly) ... But in any case, please note that in quoting
Price I am not proposing an explanation, or even taking a position, I am
only pointing out that there is the logical possibility that an explanation
could be constructed on this basis.

So, I am merely pointing out that when someone says Bell made exactly 3
assumptions... that isn't true, so anything we deduce on the basis of him
having made exactly 3 assumptions will be false (or at best, only
accidentally true). And hence, until the 4th assumption is either
incorportated into an explanation of BI violations, or shown to be
irrelevant to them, we will not be in a position to say EPR shows that
physics is either non-local or non-realistic.

Everything else I've said on this subject has been in response to people
trying to argue that physics is not time symmetric. So far all such
arguments have been a variant on the second law says so and my response
has been a variant on the second law emerges above the level at which we
can detect time symmetry. (Plus I've invoked boundary conditions on the
universe to explain how the second law can arise from time symmetric
physics...)

However, I don't have the technical knowledge to either construct an
explanation of EPR on this basis, or to show that one can't be constructed.

But I do think it's high time someone did, if they haven't already done so.

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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/16/2014 10:32 AM, Jason Resch wrote:


They only 'seem to' because you neglect the fact that in the experiment you 
don't
use the digits of pi from Platonia, you use their physical instantiation as
calculated in the registers of a computer or written ink on a page.


And what is the physical link between the computer's registers and the 
radioactive decay?


They have common events in their past light cone.


What keeps it from breaking down in the next moment?


Why are there regularities that can be represented by the laws of phyiscs?  
Dunno.

Brent

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Re: What are wavefunctions?

2014-01-16 Thread LizR
On 17 January 2014 12:31, meekerdb meeke...@verizon.net wrote:

  On 1/16/2014 10:32 AM, Jason Resch wrote:

  They only 'seem to' because you neglect the fact that in the experiment
 you don't use the digits of pi from Platonia, you use their physical
 instantiation as calculated in the registers of a computer or written ink
 on a page.


  And what is the physical link between the computer's registers and the
 radioactive decay?


 They have common events in their past light cone.

  What keeps it from breaking down in the next moment?


 Why are there regularities that can be represented by the laws of
 phyiscs?  Dunno.


One can probably imagine answers with a little effort (WAP, parsimony...)
but Dunno is the honest answer.

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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/16/2014 11:00 AM, LizR wrote:
On 17 January 2014 07:56, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net 
wrote:


On 1/16/2014 1:48 AM, LizR wrote:

On 16 January 2014 20:00, meekerdb meeke...@verizon.net
mailto:meeke...@verizon.net wrote:

On 1/15/2014 7:08 PM, LizR wrote:

On 16 January 2014 14:11, meekerdb meeke...@verizon.net
mailto:meeke...@verizon.net wrote:


You can do that (in fact it may have been done).  You have two 
emitters
with polarizers and a detector at which you post-select only those
particles that arrive and form a singlet.  Then you will find that 
the
correlation counts for that subset violates Bell's inequality for
polarizer settings of 30, 60, 120deg.

I assume that means Price's (and Bell's) assumption that violations of 
Bell's
inequality can be explained locally and realistically with time 
symmetry is
definitely wrong...?


?? Why do you conclude that?  It's the time-reverse of the EPR that 
violated BI.

Because as I (perhaps mis-) understand it, Price claims that we need to 
take both
past AND future boundary conditions into account to explain EPR with time 
symmetry.
If we can explain it with only a forward in time or backward in time 
explanation,
then we aren't using both.


But in the reverse EPR we are in effect using both past and future boundary
conditions.  At the emitters we set the polarizers - that's the past 
boundary
condition.  At the single detector we post-select only those incoming pairs 
that
form a net-zero spin; so that's a future boundary condition.


I must admit I thought you were saying we could do it using ONLY the future boundary 
conditions. If you use both then you should logically use both in the forwards case, 
too, so I assume Price's explanation still stands.


You do use both in the forward case, but people kind of slide over the initial condition 
which is that you produce two particles with net-zero spin.  It might seem more symmetric 
if we did the forward case by creating a lot of pairs and only selecting the net spin-zero 
pairs to go to the EPR detectors.


Brent

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Re: What are wavefunctions?

2014-01-16 Thread LizR
On 17 January 2014 12:42, meekerdb meeke...@verizon.net wrote:

 You do use both in the forward case, but people kind of slide over the
 initial condition which is that you produce two particles with net-zero
 spin.  It might seem more symmetric if we did the forward case by creating
 a lot of pairs and only selecting the net spin-zero pairs to go to the EPR
 detectors.


I can kind of see how (in this explanation) this would merge the
information from the future, so the particles could effectively influence
each other at a distance at the detectors.

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Re: What are wavefunctions?

2014-01-16 Thread Jason Resch
On Thu, Jan 16, 2014 at 5:31 PM, meekerdb meeke...@verizon.net wrote:

  On 1/16/2014 10:32 AM, Jason Resch wrote:

  They only 'seem to' because you neglect the fact that in the experiment
 you don't use the digits of pi from Platonia, you use their physical
 instantiation as calculated in the registers of a computer or written ink
 on a page.


  And what is the physical link between the computer's registers and the
 radioactive decay?


 They have common events in their past light cone.


But is that enough to explain the link? It permits a non-superluminal link,
but what is that link, if not some spooky, invisible,
causal-agreement-enforcening mechanism?



  What keeps it from breaking down in the next moment?


 Why are there regularities that can be represented by the laws of
 phyiscs?  Dunno.


But here, there regularities are not from following from any laws, at least
not compressible ones.

Jason



 Brent

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Re: What are wavefunctions?

2014-01-16 Thread meekerdb

On 1/16/2014 4:46 PM, Jason Resch wrote:




On Thu, Jan 16, 2014 at 5:31 PM, meekerdb meeke...@verizon.net 
mailto:meeke...@verizon.net wrote:


On 1/16/2014 10:32 AM, Jason Resch wrote:


They only 'seem to' because you neglect the fact that in the experiment 
you
don't use the digits of pi from Platonia, you use their physical 
instantiation
as calculated in the registers of a computer or written ink on a page.


And what is the physical link between the computer's registers and the 
radioactive
decay?


They have common events in their past light cone.


But is that enough to explain the link? It permits a non-superluminal link, but what is 
that link, if not some spooky, invisible, causal-agreement-enforcening mechanism?


Dunno, but it needn't be spooky; since the detectors, polarizers, emitters, experiment, 
are all macroscopic and semi-classical they presumably are entangled with everything in 
their past light cones via ordinary QM particle/fields - that's the hypothesis of how 
decoherence can split the Everett world into quasi-classical ones we can experience.


Brent




What keeps it from breaking down in the next moment?


Why are there regularities that can be represented by the laws of phyiscs?  
Dunno.


But here, there regularities are not from following from any laws, at least not 
compressible ones.


Jason


Brent

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Re: What are wavefunctions?

2014-01-15 Thread Bruno Marchal


On 14 Jan 2014, at 22:04, LizR wrote:

Sorry, I realise that last sentence could be misconstrued by someone  
who's being very nitpicky and looking for irrelevant loopholes to  
argue about, so let's try again.


Now how about discussing what I've actually claimed, that the time  
symmetry of fundamental physics could account for the results  
obtained in EPR experiments?


Logically, yes.

But you need hyper-determinism, that is you need to select very  
special boundary conditions, which makes Cramer's transaction theory  
close to Bohm's theory.


Those are still many-world theories, + some ugly selection principle  
to get one branch. It is very not natural, as you have quasi  
microsuperposition (appearance of many branches), but the macro-one  
are eliminated by ad hoc boundary conditions, which will differ  
depending on where you will decide to introduce the Heisenberg cut.  
Also, QM will prevent us to know or measure those boundary conditions,  
which makes them into (local, perhaps, in *some* sense) hidden  
variable theory.


Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and  
the boundary conditions does not play any special role, and indeed  
they are all realized in the universal wave (and in arithmetic).


Bruno







On 15 January 2014 10:01, LizR lizj...@gmail.com wrote:
On 15 January 2014 06:11, John Clark johnkcl...@gmail.com wrote:
On Sun, Jan 12, 2014 at 6:41 PM, LizR lizj...@gmail.com wrote:

 Retro-causality (time symmetry is a better term) only exists  
at the quantum level.


 Why? Where is the dividing line? And with a Schrodinger's Cat  
type device a quantum event can easily be magnified to a macro-event  
as large as desired, you could connect it up to an H-bomb.


 The dividing line appears to be roughly where decoherence occurs.  
Basically anything above a single quantum entity engaged in a  
carefully controlled interaction is liable to get its time symmetric  
properties washed out by interactions with other particles


The nucleus of an atom is tiny even by atomic standards so it is  
certainly at the quantum level, and in its natural state of existing  
inside a huge chunk of irregular gyrating matter this tiny thing is  
constantly subject to the slings and arrows of outrageous fortune  
from an astronomical number of other clumsy atoms; and yet the half  
life of Bismuth 209 is 1.9 * 10^19 years. Why?


Because that's how long it takes for the relevant particles to get  
over the potential barrier. But this is irrelevant. Atomic nuclei  
are (probably) already on the wrong side of the entropy fence in  
any case. They're bound states which can only occur under certain  
special cirumstances, namely when the universe expands and cools  
enough to allow them to form. And atomic nuclei haven't been used to  
violate Bell's inequality as far as I know.



 It's just a fact, if time were symmetrical then you'd be just as  
good at predicting the future as you are at remembering the past, so  
you'd know the outcome of an experiment before you performed it just  
as well as you remember setting up the apparatus. But this is not  
the way things are because the second law exists. And the second law  
exists because of low entropy initial conditions. And I don't know  
why there were low entropy initial conditions.


 OK. So the above statement of yours about predicting the future is  
still false,


Yes it's false, I don't think this will come as a great news flash  
but the truth is we're not as good at predicting the future as we  
are at remembering the past. And the reason we're not is that time  
is not symmetrical.


Except below the level of coarse graining at which entropy operates,  
that is correct. And I never claimed otherwise. As I keep saying,  
I'm only claiming this is relevant in special circumstances like EPR  
experiments.


 To recap briefly -- the laws of physics are time symmetrical,

Yes, the fundamental laws of physics, the ones we know anyway, seem  
to be time symmetrical. But that doesn't mean that time is  
symmetrical.


...is just words. Stop nitpicking. If the laws of physics are time  
symmetrical, that has a potential influence on EPR experiments.


 and most particle interactions are constrained by boundary  
conditions.


Yes, and that is why time is NOT symmetrical.

Stop playing with words. The time symmetry of fundamental physics is  
there, so it's perfectly valid to say time is symmetrical below the  
level of coarse graining needed to derive the 2nd law, and  
asymmetrical above it. (That's virtually a simple restatement of  
Boltzmann's H-theorem for dummies.) The point is that symmetrical  
time may become apparent in EPR setups. You haven't yet given even a  
suggestion of a reason why it wouldn't, just a load of hand waving  
about stuff that is IRRELEVANT to EPR experiments, which are  
carefully prepared to avoid all the influences you've mentioned.


Now how about discussing what I've actually claimed, 

Re: What are wavefunctions?

2014-01-15 Thread LizR
On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone who's
 being very nitpicky and looking for irrelevant loopholes to argue about, so
 let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very special
 boundary conditions, which makes Cramer's transaction theory close to
 Bohm's theory.


I'm not sure what you mean by special boundary conditions. The bcs in an
Aspect type experiment are the device which creates the photons, and the
settings of the measuring apparatuses. These are special but only in that
the photons are entangled ... note that this isn't Cramer's or Bohm's
theory (the transaction theory requires far more complexity that this).


 Those are still many-world theories, + some ugly selection principle to
 get one branch. It is very not natural, as you have quasi
 microsuperposition (appearance of many branches), but the macro-one are
 eliminated by ad hoc boundary conditions, which will differ depending on
 where you will decide to introduce the Heisenberg cut. Also, QM will
 prevent us to know or measure those boundary conditions, which makes them
 into (local, perhaps, in *some* sense) hidden variable theory.


I don't understand the above. The theory is simply QM with no collapse and
with no preferred time direction (it assumes any system which violates
Bell's inequality has to operate below the level where decoherence brings
in the effects of the entropy gradient). It is both local and realistic,
since time symmetry is Bell's 4th assumption - it allows EPR experiments
to be local and realistic (I am relying on John Bell for this information,
I wouldn't be able to work it out myself). So it definitely is a hidden
variable theory.

I think for it to work the system is kept from undergoing decoherence or
any interaction that would lead to MWI branching. EPR experiments only
appear to work for systems that are shielded from such effects, I think? So
there isn't a problem with the MWI - the whole thing takes place in one
branch, with no quantum interfence etc being relevant. (I believe that EPR
experiments lose their ability to violate Bell's inequality once
interactions occur that could cause MWI branching within the system under
consideration???)


 Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and the
 boundary conditions does not play any special role, and indeed they are all
 realized in the universal wave (and in arithmetic).


Please explain about the Heisenberg cut. I've heard the term, but don't
know how it relates to EPR experiments.

Have you read Huw Price's book Time's arrow and Archimedes' Point ?

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Re: What are wavefunctions?

2014-01-15 Thread Bruno Marchal


On 15 Jan 2014, at 11:10, LizR wrote:


On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:

On 14 Jan 2014, at 22:04, LizR wrote:

Sorry, I realise that last sentence could be misconstrued by  
someone who's being very nitpicky and looking for irrelevant  
loopholes to argue about, so let's try again.


Now how about discussing what I've actually claimed, that the time  
symmetry of fundamental physics could account for the results  
obtained in EPR experiments?


Logically, yes.

But you need hyper-determinism, that is you need to select very  
special boundary conditions, which makes Cramer's transaction theory  
close to Bohm's theory.


I'm not sure what you mean by special boundary conditions. The bcs  
in an Aspect type experiment are the device which creates the  
photons, and the settings of the measuring apparatuses.


The setting of the analyser must be predetermined. And not in the  
mechanist sense, where the choice of the analyser is still made by  
you, even if deterministically so. With only one branch, you are not  
just using irreversibility, but you are using the boundary condition  
selecting a branch among all in the universal wave.





These are special but only in that the photons are entangled ...  
note that this isn't Cramer's or Bohm's theory (the transaction  
theory requires far more complexity that this).


Those are still many-world theories, + some ugly selection  
principle to get one branch. It is very not natural, as you have  
quasi microsuperposition (appearance of many branches), but the  
macro-one are eliminated by ad hoc boundary conditions, which will  
differ depending on where you will decide to introduce the  
Heisenberg cut. Also, QM will prevent us to know or measure those  
boundary conditions, which makes them into (local, perhaps, in  
*some* sense) hidden variable theory.


I don't understand the above. The theory is simply QM with no  
collapse and with no preferred time direction (it assumes any system  
which violates Bell's inequality has to operate below the level  
where decoherence brings in the effects of the entropy gradient). It  
is both local and realistic, since time symmetry is Bell's 4th  
assumption - it allows EPR experiments to be local and realistic (I  
am relying on John Bell for this information, I wouldn't be able to  
work it out myself). So it definitely is a hidden variable theory.


Yes, and I am willing to accept it is local. but it is hyper- 
determined. It means that if I chose the setting of the two analyser  
in the Aspect experience by looking at my horoscope, that horoscope  
was determined by the whole future of the phsyical universe. Logically  
possible, you are right, but ugly, as it is a selection principle  
based on boundary conditions. It is more local than Bohm, and it  
does not need a new potential, but it is sill using abnormal special  
data for the TOE. It is no more a nice and gentle equation like the  
SWE, but that same equation together with tuns of mega-terra-gigabyte  
of data.





I think for it to work the system is kept from undergoing  
decoherence or any interaction that would lead to MWI branching. EPR  
experiments only appear to work for systems that are shielded from  
such effects, I think? So there isn't a problem with the MWI - the  
whole thing takes place in one branch, with no quantum interfence  
etc being relevant. (I believe that EPR experiments lose their  
ability to violate Bell's inequality once interactions occur that  
could cause MWI branching within the system under consideration???)


?





Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and  
the boundary conditions does not play any special role, and indeed  
they are all realized in the universal wave (and in arithmetic).


Please explain about the Heisenberg cut. I've heard the term, but  
don't know how it relates to EPR experiments.


The Heinsenberg cut is where the wave should collapse in the  
Copenhagen QM.

Von Neumann understood well that it is largely arbitrary.

In all one world theory, you have to justify why the superposition  
works so well for the micro-worlds, and disappear for the macro- 
world.  Using reversiblity, cannot by itself solve that problem. What  
works is reversibility and the boundaries conditions. God needs to  
know all the detail of the big crunch to program convenably the big  
bang, so as making an Aspect result consistent with one-world,  
locality and determinacy.







Have you read Huw Price's book Time's arrow and Archimedes' Point ?


No. I know it,  as it is often discussed on forums.

I am not convinced, as I tend to not believe in any primitive time and  
space, at least when I tend to believe in comp (of course I *know*  
nothing).


QM is indeed reversible (in large part), but using this to select one  
branch by boundary condition, is still like a form of cosmic solipsism  
to me. We can't refute it, and unlike most QM collapse theories, we 

Re: What are wavefunctions?

2014-01-15 Thread Jesse Mazer
On Wed, Jan 15, 2014 at 5:10 AM, LizR lizj...@gmail.com wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very special
 boundary conditions, which makes Cramer's transaction theory close to
 Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses. These are special but only in that
 the photons are entangled ... note that this isn't Cramer's or Bohm's
 theory (the transaction theory requires far more complexity that this).



Time symmetry in the laws of physics alone, without any special restriction
on boundary conditions, can't get you violation of Bell inequalities.
Ordinary time symmetry doesn't mean you have to take into account both
future and past to determine what happens in a given region of spacetime
after all, it just means you can deduce it equally well going in *either*
direction. So in a deterministic time-symmetric theory (Price's
speculations about hidden variables are at least compatible with
determinism) it's still true that what happens in any region of spacetime
can be determined entirely by events in its past light cone, say the ones
occurring at some arbitrarily-chosen initial tim. This means that in a
Price-like theory where measurement results are explained in terms of
hidden variables the particles carry with them from emitter to
experimenters, it must be true that the original assignment of the hidden
variables to each particle at the emitter is determined by the past light
cone of the event of each particle leaving the emitter. Meanwhile, the
event of an experimenter choosing which measurement to perform will have
its own past light cone, and there are plenty of events in the past light
cone of the choice that do *not* lie in the past light cone of the
particles leaving the emitter.

So, without any restriction on boundary conditions, one can choose an
ensemble of possible initial conditions with the following properties:

1. The initial states of all points in space that line in the past light
cone of the particles leaving the emitter are identical for each member of
the ensemble, so in every possible history generated from these initial
conditions, the particles have the same hidden variables associated with
them.

2. The initial states of points in space that lie in the past light cone of
the experimenters choosing what spin direction to measure vary in different
members of the ensemble, in such a way that all combinations of measurement
choices are represented in different histories chosen from this ensemble.

If both these conditions apply, Bell's proofs that various inequalities
shouldn't be violated works just fine--for example, there's no combination
of hidden variables you can choose for the particle pair that ensure that
in all the histories where the experimenters measure along the *same* axis
they get opposite results (spin-up for one experimenter, spin-down for the
other) with probability 1, but in all the histories where they measure
along two *different* axes they have less than a 1/3 chance of getting
opposite results. Only by having the hidden variables assigned during
emission be statistically correlated to the choices the experimenters later
make about measurements can Price's argument work, and the argument above
shows that time-symmetry without special boundary conditions won't suffice
for this.

Jesse






 Those are still many-world theories, + some ugly selection principle to
 get one branch. It is very not natural, as you have quasi
 microsuperposition (appearance of many branches), but the macro-one are
 eliminated by ad hoc boundary conditions, which will differ depending on
 where you will decide to introduce the Heisenberg cut. Also, QM will
 prevent us to know or measure those boundary conditions, which makes them
 into (local, perhaps, in *some* sense) hidden variable theory.


 I don't understand the above. The theory is simply QM with no collapse and
 with no preferred time direction (it assumes any system which violates
 Bell's inequality has to operate below the level where decoherence brings
 in the effects of the entropy gradient). It is both local and realistic,
 since time symmetry is Bell's 4th assumption - it allows EPR experiments
 to be local and realistic (I am relying on John Bell for this information,
 I wouldn't be able to work it out myself). So it definitely is a hidden
 variable theory.

 I think for it to work 

Re: What are wavefunctions?

2014-01-15 Thread Richard Ruquist
On Wed, Jan 15, 2014 at 7:13 AM, Bruno Marchal marc...@ulb.ac.be wrote:


 On 15 Jan 2014, at 11:10, LizR wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very special
 boundary conditions, which makes Cramer's transaction theory close to
 Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses.


 The setting of the analyser must be predetermined. And not in the
 mechanist sense, where the choice of the analyser is still made by you,
 even if deterministically so. With only one branch, you are not just using
 irreversibility, but you are using the boundary condition selecting a
 branch among all in the universal wave.


In Wheeler's 'ItBit' empirical quantum model, that is because in
controlled experiments the detector observers on the detection plane all
ask the same question, thereby always selecting the same spacetime/branch
for photon statistics.





 These are special but only in that the photons are entangled ... note that
 this isn't Cramer's or Bohm's theory (the transaction theory requires far
 more complexity that this).


 Those are still many-world theories, + some ugly selection principle to
 get one branch. It is very not natural, as you have quasi
 microsuperposition (appearance of many branches), but the macro-one are
 eliminated by ad hoc boundary conditions, which will differ depending on
 where you will decide to introduce the Heisenberg cut. Also, QM will
 prevent us to know or measure those boundary conditions, which makes them
 into (local, perhaps, in *some* sense) hidden variable theory.


 I don't understand the above. The theory is simply QM with no collapse and
 with no preferred time direction (it assumes any system which violates
 Bell's inequality has to operate below the level where decoherence brings
 in the effects of the entropy gradient). It is both local and realistic,
 since time symmetry is Bell's 4th assumption - it allows EPR experiments
 to be local and realistic (I am relying on John Bell for this information,
 I wouldn't be able to work it out myself). So it definitely is a hidden
 variable theory.


 Yes, and I am willing to accept it is local. but it is hyper-determined.
 It means that if I chose the setting of the two analyser in the Aspect
 experience by looking at my horoscope, that horoscope was determined by the
 whole future of the phsyical universe. Logically possible, you are right,
 but ugly, as it is a selection principle based on boundary conditions. It
 is more local than Bohm, and it does not need a new potential, but it is
 sill using abnormal special data for the TOE. It is no more a nice and
 gentle equation like the SWE, but that same equation together with tuns of
 mega-terra-gigabyte of data.


Same comment as above but now controlled experiments also use the gentle
equation like the SWE', but still in the context of an MWI reality. Richard




 I think for it to work the system is kept from undergoing decoherence or
 any interaction that would lead to MWI branching. EPR experiments only
 appear to work for systems that are shielded from such effects, I think? So
 there isn't a problem with the MWI - the whole thing takes place in one
 branch, with no quantum interfence etc being relevant. (I believe that EPR
 experiments lose their ability to violate Bell's inequality once
 interactions occur that could cause MWI branching within the system under
 consideration???)

 A recent paper suggests that decoherence in the experiment particle
preparations are a stronger source of branching than decoherence in the
detector. In terms of Wheeler theory, that amounts to the initial observer,
the prepemit particle observer, being more capable of producing branching
by asking a variety of questions (decohered questions) or even random
questions, than the final detector observer asking just random questions is
capable of producing branching..
http://phys.org/news/2014-01-quantum-to-classical-transition-fuzziness.html


 ?




 Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and the
 boundary conditions does not play any special role, and indeed they are all
 realized in the universal wave (and in arithmetic).


 Please explain about the Heisenberg cut. I've heard the term, but don't
 know how it relates to EPR experiments.


 The Heinsenberg cut is where the wave should collapse in the Copenhagen
 QM.
 Von Neumann 

Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 4:13 AM, Bruno Marchal wrote:
I am not convinced, as I tend to not believe in any primitive time and space, at least 
when I tend to believe in comp (of course I *know* nothing).


QM is indeed reversible (in large part), but using this to select one branch by boundary 
condition, is still like a form of cosmic solipsism to me. We can't refute it, and 
unlike most QM collapse theories, we can't criticize it from locality and determinacy, 
but that does not yet make it convincing compare to MW, and infinitely more so in the 
comp frame, where we can't avoid the many dreams.


It's just information from the future - which is exactly the same thing as true 
randomness, and both are operationally the same as FPI. That's why I think an advancement 
in QM interpretation would be to derive probability.  Comp provides an explanation of 
randomness, but it's not clear to me that it implies a complex Hilbert space.


Brent

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Re: What are wavefunctions?

2014-01-15 Thread LizR
On 16 January 2014 01:13, Bruno Marchal marc...@ulb.ac.be wrote:


 On 15 Jan 2014, at 11:10, LizR wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very special
 boundary conditions, which makes Cramer's transaction theory close to
 Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses.


 The setting of the analyser must be predetermined. And not in the
 mechanist sense, where the choice of the analyser is still made by you,
 even if deterministically so. With only one branch, you are not just using
 irreversibility, but you are using the boundary condition selecting a
 branch among all in the universal wave.

 You mean the measuring devices? If so, of course they are predetermined -
as is the state of the emitter. Time symmetric physics would guarantee
that. I don't see that is special, however. (But I will read on :)



 These are special but only in that the photons are entangled ... note that
 this isn't Cramer's or Bohm's theory (the transaction theory requires far
 more complexity that this).


 Those are still many-world theories, + some ugly selection principle to
 get one branch. It is very not natural, as you have quasi
 microsuperposition (appearance of many branches), but the macro-one are
 eliminated by ad hoc boundary conditions, which will differ depending on
 where you will decide to introduce the Heisenberg cut. Also, QM will
 prevent us to know or measure those boundary conditions, which makes them
 into (local, perhaps, in *some* sense) hidden variable theory.


 I don't understand the above. The theory is simply QM with no collapse and
 with no preferred time direction (it assumes any system which violates
 Bell's inequality has to operate below the level where decoherence brings
 in the effects of the entropy gradient). It is both local and realistic,
 since time symmetry is Bell's 4th assumption - it allows EPR experiments
 to be local and realistic (I am relying on John Bell for this information,
 I wouldn't be able to work it out myself). So it definitely is a hidden
 variable theory.


 Yes, and I am willing to accept it is local. but it is hyper-determined.
 It means that if I chose the setting of the two analyser in the Aspect
 experience by looking at my horoscope, that horoscope was determined by the
 whole future of the phsyical universe. Logically possible, you are right,
 but ugly, as it is a selection principle based on boundary conditions. It
 is more local than Bohm, and it does not need a new potential, but it is
 sill using abnormal special data for the TOE. It is no more a nice and
 gentle equation like the SWE, but that same equation together with tuns of
 mega-terra-gigabyte of data.

 I don't follow the whole future business. I'm only talking about what
might be called micro-symmetry - symmetry below the level of
coarse-graining at which entropic processes emerge. This is particularly
not a problem in a block universe, or block multiverse, where there is no
moving arrow of time and the outcomes are already there (maybe in
multiple branches in the MWI). Where / why is all that extra data required?



 I think for it to work the system is kept from undergoing decoherence or
 any interaction that would lead to MWI branching. EPR experiments only
 appear to work for systems that are shielded from such effects, I think? So
 there isn't a problem with the MWI - the whole thing takes place in one
 branch, with no quantum interfence etc being relevant. (I believe that EPR
 experiments lose their ability to violate Bell's inequality once
 interactions occur that could cause MWI branching within the system under
 consideration???)


 ?


I may be wrong on this, but I believe EPR experiments require that the
particles being measured are isolated from decoherence - and hence from
branching, in the MWI. So the MWI can be ignored for the purposes of
analysing the experiment. Any proposed explanation for violations of Bell's
inequality, therefore, should take into account what is logically possible
if time is directionally neutral at the level of the particles being
measured.

LATER NOTE - see below for me revising my ideas on this!



 Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and the
 boundary conditions does not play any special role, and indeed they are all
 realized in the universal wave (and in arithmetic).


 Please explain about 

Re: What are wavefunctions?

2014-01-15 Thread LizR
On 16 January 2014 03:51, Jesse Mazer laserma...@gmail.com wrote:


 On Wed, Jan 15, 2014 at 5:10 AM, LizR lizj...@gmail.com wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very
 special boundary conditions, which makes Cramer's transaction theory close
 to Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses. These are special but only in that
 the photons are entangled ... note that this isn't Cramer's or Bohm's
 theory (the transaction theory requires far more complexity that this).



 Time symmetry in the laws of physics alone, without any special
 restriction on boundary conditions, can't get you violation of Bell
 inequalities. Ordinary time symmetry doesn't mean you have to take into
 account both future and past to determine what happens in a given region of
 spacetime after all, it just means you can deduce it equally well going in
 *either* direction. So in a deterministic time-symmetric theory (Price's
 speculations about hidden variables are at least compatible with
 determinism) it's still true that what happens in any region of spacetime
 can be determined entirely by events in its past light cone, say the ones
 occurring at some arbitrarily-chosen initial tim. This means that in a
 Price-like theory where measurement results are explained in terms of
 hidden variables the particles carry with them from emitter to
 experimenters, it must be true that the original assignment of the hidden
 variables to each particle at the emitter is determined by the past light
 cone of the event of each particle leaving the emitter. Meanwhile, the
 event of an experimenter choosing which measurement to perform will have
 its own past light cone, and there are plenty of events in the past light
 cone of the choice that do *not* lie in the past light cone of the
 particles leaving the emitter.

 So, without any restriction on boundary conditions, one can choose an
 ensemble of possible initial conditions with the following properties:

 1. The initial states of all points in space that line in the past light
 cone of the particles leaving the emitter are identical for each member of
 the ensemble, so in every possible history generated from these initial
 conditions, the particles have the same hidden variables associated with
 them.

 2. The initial states of points in space that lie in the past light cone
 of the experimenters choosing what spin direction to measure vary in
 different members of the ensemble, in such a way that all combinations of
 measurement choices are represented in different histories chosen from this
 ensemble.

 If both these conditions apply, Bell's proofs that various inequalities
 shouldn't be violated works just fine--for example, there's no combination
 of hidden variables you can choose for the particle pair that ensure that
 in all the histories where the experimenters measure along the *same* axis
 they get opposite results (spin-up for one experimenter, spin-down for the
 other) with probability 1, but in all the histories where they measure
 along two *different* axes they have less than a 1/3 chance of getting
 opposite results. Only by having the hidden variables assigned during
 emission be statistically correlated to the choices the experimenters later
 make about measurements can Price's argument work, and the argument above
 shows that time-symmetry without special boundary conditions won't suffice
 for this.

 If you're right then Price is wrong. However I don't recall him saying
that the only consequence of time symmetry is that events can be, so to
speak, worked backwards equally well. In particular, I read his EPR
explanation as showing that both future and past boundary conditions were
relevant in explaining the violations of B's Inequality. The
forwards-and-backwards version would prevent time symmetry having any
detectable effects, as far as I can see. (Also I'd like to see an
explanation of EPR which works backwards from the measurement settings to
the emitter and explains the violation of B's Inequality. That would
definitely be a clincher!)

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Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 4:03 PM, LizR wrote:
By the way, I may have this wrong but it seems to me your hyperdeterminism objection 
is an objection to block universes generally. I can't see how the big crunch (or 
timelike infinity) being a boundary condition on the universe is a problem in a block 
universe (or multiverse) ...?


I think Bruno is thinking of a tree-like branching block multiverse so there can still 
be FPI due to the branches.  Otherwise definite, random things have to happen in realizing 
the block universe - and Bruno hates random things and he likes infinities, so...  But you 
should read L.S. Schulman's solution to the problem of randomness. He speculates that 
within the domain of a state we can prepare, which is of measure hbar=/=0, there are 
special states which are causally connected to *future* states and when we choose a 
measurement in the future we are selecting out one of these special states.


Brent

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Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 4:08 PM, LizR wrote:
On 16 January 2014 03:51, Jesse Mazer laserma...@gmail.com 
mailto:laserma...@gmail.com wrote:



On Wed, Jan 15, 2014 at 5:10 AM, LizR lizj...@gmail.com 
mailto:lizj...@gmail.com
wrote:

On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be
mailto:marc...@ulb.ac.be wrote:


On 14 Jan 2014, at 22:04, LizR wrote:


Sorry, I realise that last sentence could be misconstrued by 
someone who's
being very nitpicky and looking for irrelevant loopholes to argue 
about, so
let's try again.

Now how about discussing what I've actually claimed, that the time 
symmetry
of fundamental physics could account for the results obtained in EPR
experiments?


Logically, yes.

But you need hyper-determinism, that is you need to select very 
special
boundary conditions, which makes Cramer's transaction theory close 
to Bohm's
theory.


I'm not sure what you mean by special boundary conditions. The bcs in 
an Aspect
type experiment are the device which creates the photons, and the 
settings of
the measuring apparatuses. These are special but only in that the 
photons are
entangled ... note that this isn't Cramer's or Bohm's theory (the 
transaction
theory requires far more complexity that this).



Time symmetry in the laws of physics alone, without any special restriction 
on
boundary conditions, can't get you violation of Bell inequalities. Ordinary 
time
symmetry doesn't mean you have to take into account both future and past to
determine what happens in a given region of spacetime after all, it just 
means you
can deduce it equally well going in *either* direction. So in a 
deterministic
time-symmetric theory (Price's speculations about hidden variables are at 
least
compatible with determinism) it's still true that what happens in any 
region of
spacetime can be determined entirely by events in its past light cone, say 
the ones
occurring at some arbitrarily-chosen initial tim. This means that in a 
Price-like
theory where measurement results are explained in terms of hidden variables 
the
particles carry with them from emitter to experimenters, it must be true 
that the
original assignment of the hidden variables to each particle at the 
emitter is
determined by the past light cone of the event of each particle leaving the 
emitter.
Meanwhile, the event of an experimenter choosing which measurement to 
perform will
have its own past light cone, and there are plenty of events in the past 
light cone
of the choice that do *not* lie in the past light cone of the particles 
leaving the
emitter.

So, without any restriction on boundary conditions, one can choose an 
ensemble of
possible initial conditions with the following properties:

1. The initial states of all points in space that line in the past light 
cone of the
particles leaving the emitter are identical for each member of the 
ensemble, so in
every possible history generated from these initial conditions, the 
particles have
the same hidden variables associated with them.

2. The initial states of points in space that lie in the past light cone of 
the
experimenters choosing what spin direction to measure vary in different 
members of
the ensemble, in such a way that all combinations of measurement choices are
represented in different histories chosen from this ensemble.

If both these conditions apply, Bell's proofs that various inequalities 
shouldn't be
violated works just fine--for example, there's no combination of hidden 
variables
you can choose for the particle pair that ensure that in all the histories 
where the
experimenters measure along the *same* axis they get opposite results 
(spin-up for
one experimenter, spin-down for the other) with probability 1, but in all 
the
histories where they measure along two *different* axes they have less than 
a 1/3
chance of getting opposite results. Only by having the hidden variables 
assigned
during emission be statistically correlated to the choices the 
experimenters later
make about measurements can Price's argument work, and the argument above 
shows that
time-symmetry without special boundary conditions won't suffice for this.

If you're right then Price is wrong. However I don't recall him saying that the only 
consequence of time symmetry is that events can be, so to speak, worked backwards 
equally well. In particular, I read his EPR explanation as showing that both future and 
past boundary conditions were relevant in explaining the violations of B's Inequality. 
The forwards-and-backwards version would prevent time symmetry having any detectable 
effects, as far as I can see. (Also I'd like to see an explanation of EPR which 

Re: What are wavefunctions?

2014-01-15 Thread LizR
On 16 January 2014 13:57, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 4:03 PM, LizR wrote:

 By the way, I may have this wrong but it seems to me your
 hyperdeterminism objection is an objection to block universes generally.
 I can't see how the big crunch (or timelike infinity) being a boundary
 condition on the universe is a problem in a block universe (or multiverse)
 ...?


 I think Bruno is thinking of a tree-like branching block multiverse so
 there can still be FPI due to the branches.  Otherwise definite, random
 things have to happen in realizing the block universe - and Bruno hates
 random things and he likes infinities, so...  But you should read L.S.
 Schulman's solution to the problem of randomness.  He speculates that
 within the domain of a state we can prepare, which is of measure hbar=/=0,
 there are special states which are causally connected to *future* states
 and when we choose a measurement in the future we are selecting out one of
 these special states.

 I am thinking of a block multiverse, too, and I can't see why future (or
past) boundary conditions are a problem. Maybe I'm being thick, it wouldn't
be the first time.

Do you have a link to that reference?

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Re: What are wavefunctions?

2014-01-15 Thread Jason Resch
Hyper determinism makes little sense as a serious theory to me. Why should
particle properties conform to what a computer's random number generator
outputs, and then the digits of Pi, and then the binary expansion of the
square root of 2, all variously as the experimenters change the knobs as to
what determines the spin axis of the lepton their analyzer measures. Are
radioactive decays of particles really such things that are governed by the
behavior of a selected random source, or alternately, are they really such
things that govern what the digits of Pi or the square root of 2 are?

Jason


On Wed, Jan 15, 2014 at 6:13 AM, Bruno Marchal marc...@ulb.ac.be wrote:


 On 15 Jan 2014, at 11:10, LizR wrote:

 On 15 January 2014 22:55, Bruno Marchal marc...@ulb.ac.be wrote:


 On 14 Jan 2014, at 22:04, LizR wrote:

 Sorry, I realise that last sentence could be misconstrued by someone
 who's being very nitpicky and looking for irrelevant loopholes to argue
 about, so let's try again.

 Now how about discussing what I've actually claimed, that the time
 symmetry of fundamental physics could account for the results obtained in
 EPR experiments?


 Logically, yes.

 But you need hyper-determinism, that is you need to select very special
 boundary conditions, which makes Cramer's transaction theory close to
 Bohm's theory.


 I'm not sure what you mean by special boundary conditions. The bcs in an
 Aspect type experiment are the device which creates the photons, and the
 settings of the measuring apparatuses.


 The setting of the analyser must be predetermined. And not in the
 mechanist sense, where the choice of the analyser is still made by you,
 even if deterministically so. With only one branch, you are not just using
 irreversibility, but you are using the boundary condition selecting a
 branch among all in the universal wave.




 These are special but only in that the photons are entangled ... note that
 this isn't Cramer's or Bohm's theory (the transaction theory requires far
 more complexity that this).


 Those are still many-world theories, + some ugly selection principle to
 get one branch. It is very not natural, as you have quasi
 microsuperposition (appearance of many branches), but the macro-one are
 eliminated by ad hoc boundary conditions, which will differ depending on
 where you will decide to introduce the Heisenberg cut. Also, QM will
 prevent us to know or measure those boundary conditions, which makes them
 into (local, perhaps, in *some* sense) hidden variable theory.


 I don't understand the above. The theory is simply QM with no collapse and
 with no preferred time direction (it assumes any system which violates
 Bell's inequality has to operate below the level where decoherence brings
 in the effects of the entropy gradient). It is both local and realistic,
 since time symmetry is Bell's 4th assumption - it allows EPR experiments
 to be local and realistic (I am relying on John Bell for this information,
 I wouldn't be able to work it out myself). So it definitely is a hidden
 variable theory.


 Yes, and I am willing to accept it is local. but it is hyper-determined.
 It means that if I chose the setting of the two analyser in the Aspect
 experience by looking at my horoscope, that horoscope was determined by the
 whole future of the phsyical universe. Logically possible, you are right,
 but ugly, as it is a selection principle based on boundary conditions. It
 is more local than Bohm, and it does not need a new potential, but it is
 sill using abnormal special data for the TOE. It is no more a nice and
 gentle equation like the SWE, but that same equation together with tuns of
 mega-terra-gigabyte of data.



 I think for it to work the system is kept from undergoing decoherence or
 any interaction that would lead to MWI branching. EPR experiments only
 appear to work for systems that are shielded from such effects, I think? So
 there isn't a problem with the MWI - the whole thing takes place in one
 branch, with no quantum interfence etc being relevant. (I believe that EPR
 experiments lose their ability to violate Bell's inequality once
 interactions occur that could cause MWI branching within the system under
 consideration???)


 ?




 Many worlds is far less ad-hoc, imo. There is no Heisenberg cut, and the
 boundary conditions does not play any special role, and indeed they are all
 realized in the universal wave (and in arithmetic).


 Please explain about the Heisenberg cut. I've heard the term, but don't
 know how it relates to EPR experiments.


 The Heinsenberg cut is where the wave should collapse in the Copenhagen
 QM.
 Von Neumann understood well that it is largely arbitrary.

 In all one world theory, you have to justify why the superposition works
 so well for the micro-worlds, and disappear for the macro-world.  Using
 reversiblity, cannot by itself solve that problem. What works is
 reversibility and the boundaries conditions. God needs to know all the
 detail of 

Re: What are wavefunctions?

2014-01-15 Thread LizR
On 16 January 2014 14:11, meekerdb meeke...@verizon.net wrote:


 You can do that (in fact it may have been done).  You have two emitters
 with polarizers and a detector at which you post-select only those
 particles that arrive and form a singlet.  Then you will find that the
 correlation counts for that subset violates Bell's inequality for polarizer
 settings of 30, 60, 120deg.

 I assume that means Price's (and Bell's) assumption that violations of
Bell's inequality can be explained locally and realistically with time
symmetry is definitely wrong...?

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Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 5:13 PM, LizR wrote:
On 16 January 2014 13:57, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net 
wrote:


On 1/15/2014 4:03 PM, LizR wrote:

By the way, I may have this wrong but it seems to me your hyperdeterminism
objection is an objection to block universes generally. I can't see how the 
big
crunch (or timelike infinity) being a boundary condition on the universe is 
a
problem in a block universe (or multiverse) ...?


I think Bruno is thinking of a tree-like branching block multiverse so 
there can
still be FPI due to the branches.  Otherwise definite, random things have 
to happen
in realizing the block universe - and Bruno hates random things and he likes
infinities, so...  But you should read L.S. Schulman's solution to the 
problem of
randomness.  He speculates that within the domain of a state we can 
prepare, which
is of measure hbar=/=0, there are special states which are causally 
connected to
*future* states and when we choose a measurement in the future we are 
selecting out
one of these special states.

I am thinking of a block multiverse, too, and I can't see why future (or past) boundary 
conditions are a problem. Maybe I'm being thick, it wouldn't be the first time.


Do you have a link to that reference?


His book

Schulman L S 1997
Time's Arrows and Quantum Measurement
(New York: Cambridge University Press)

also
http://arxiv.org/pdf/1310.2602.pdf

Brent

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Re: What are wavefunctions?

2014-01-15 Thread LizR
Thanks. I probably haven't time for the book, but will try to understand
the paper.


On 16 January 2014 16:47, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 5:13 PM, LizR wrote:

  On 16 January 2014 13:57, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 4:03 PM, LizR wrote:

 By the way, I may have this wrong but it seems to me your
 hyperdeterminism objection is an objection to block universes generally.
 I can't see how the big crunch (or timelike infinity) being a boundary
 condition on the universe is a problem in a block universe (or multiverse)
 ...?


  I think Bruno is thinking of a tree-like branching block multiverseso 
 there can still be FPI due to the branches.  Otherwise definite, random
 things have to happen in realizing the block universe - and Bruno hates
 random things and he likes infinities, so...  But you should read L.S.
 Schulman's solution to the problem of randomness.  He speculates that
 within the domain of a state we can prepare, which is of measure hbar=/=0,
 there are special states which are causally connected to *future* states
 and when we choose a measurement in the future we are selecting out one of
 these special states.

  I am thinking of a block multiverse, too, and I can't see why future
 (or past) boundary conditions are a problem. Maybe I'm being thick, it
 wouldn't be the first time.

 Do you have a link to that reference?


 His book

 Schulman L S 1997
 Time’s Arrows and Quantum Measurement
 (New York: Cambridge University Press)

 also
 http://arxiv.org/pdf/1310.2602.pdf

 Brent

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Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 7:05 PM, Jason Resch wrote:
Hyper determinism makes little sense as a serious theory to me. Why should particle 
properties conform to what a computer's random number generator outputs, and then the 
digits of Pi, and then the binary expansion of the square root of 2, all variously as 
the experimenters change the knobs as to what determines the spin axis of the lepton 
their analyzer measures. Are radioactive decays of particles really such things that are 
governed by the behavior of a selected random source, or alternately, are they really 
such things that govern what the digits of Pi or the square root of 2 are?


They are all part of the same reality.  You assume its the experimental choice of 
measurement that determines the particles response, but I think the picture is supposed to 
be that both the particle in the experiment and the particles making up the experimenter 
are determined by the same laws.


Brent

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Re: What are wavefunctions?

2014-01-15 Thread meekerdb

On 1/15/2014 7:08 PM, LizR wrote:
On 16 January 2014 14:11, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net 
wrote:



You can do that (in fact it may have been done).  You have two emitters with
polarizers and a detector at which you post-select only those particles 
that arrive
and form a singlet.  Then you will find that the correlation counts for 
that subset
violates Bell's inequality for polarizer settings of 30, 60, 120deg.

I assume that means Price's (and Bell's) assumption that violations of Bell's inequality 
can be explained locally and realistically with time symmetry is definitely wrong...?


?? Why do you conclude that?  It's the time-reverse of the EPR that violated BI.

Brent

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Re: What are wavefunctions?

2014-01-15 Thread Jason Resch
On Thu, Jan 16, 2014 at 12:58 AM, meekerdb meeke...@verizon.net wrote:

  On 1/15/2014 7:05 PM, Jason Resch wrote:

 Hyper determinism makes little sense as a serious theory to me. Why should
 particle properties conform to what a computer's random number generator
 outputs, and then the digits of Pi, and then the binary expansion of the
 square root of 2, all variously as the experimenters change the knobs as to
 what determines the spin axis of the lepton their analyzer measures. Are
 radioactive decays of particles really such things that are governed by the
 behavior of a selected random source, or alternately, are they really such
 things that govern what the digits of Pi or the square root of 2 are?


 They are all part of the same reality.


Are they? Aren't numbers like Pi and sqrt(2) beyond the reality of QM, or
rather, more fundamental than it? The moment you admit numbers like Pi into
your reality, you get much more than just QM.


 You assume its the experimental choice of measurement that determines the
 particles response, but I think the picture is supposed to be that both the
 particle in the experiment and the particles making up the experimenter are
 determined by the same laws.


So how, when using the digits of Pi to decide whether to measure the
x-axis, or the y-axis, does the particle (when it decays), know to have
both electron and positron agree measured on some axis, when that axis is
determined by some relation between a circle and its diameter? Here the
laws involved seemed to go beyond physical laws, it introduces
mathematical laws, which can selectively be made to control/guide
physics..

Jason

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Re: What are wavefunctions?

2014-01-14 Thread John Clark
On Sun, Jan 12, 2014 at 1:22 PM, Jesse Mazer laserma...@gmail.com wrote:

 We know better than to think classical physics represents an exact
 description of our universe, but it certainly describes a logically
 possible mathematical universe


Maybe but we don't know that with certainty, if we ever find a Theory of
Everything we might find that classical physics is logically self
contradictory.

 if you believe in some hidden-variable theory, ANY hidden-variable
 theory, then you know that if things are realistic AND local then Bell's
 inequality can NEVER be violated; and that would be true in every corner of
 the multiverse provided that basic logic and arithmetic  is as true there
 as here.  But experiment has shown unequivocally that Bell's inequality IS
 violated. So you tell me, what conclusions can a logical person can draw
 from that?


  It tells us that either we must use a nonlocal hidden variables
 interpretation like Bohmian mechanics


Yes, things might be nonlocal.

  or that hidden variables are wrong.


Yes, things might not be realistic.  And things might not be local or
realistic.

 Did you understand that in the sentence above that you quoted, I was
 saying that there is nothing in principle preventing you from determining
 an exact quantum state for a system


You can know the exact quantum state for a system, that is to say you can
know the exact wave function BUT that deals in nothing observable like
position or momentum; you must square that complex function for that and
even then it only gives you a probability not a exactitude. And it's even
worse than that because it is a complex function so two very different
functions ( F(x)=2 and F(x) = -2 for a trivial example) can produce the
same number when squared, and thus the same probability.

 You said it yourself, the rules of the Game of Life are NOT reversible,
 that means there is more than one way for something to get into a given
 state. And the present entropy of a system is defined by Boltzman as the
 logarithm of the number of ways the system could have gotten into the state
 it's in now, therefore every application of one of the fundamental rules of
 physics in the Game of Life universe can only increase entropy.


  You are failing to specify whether you mean state to refer to
 microstate or macrostate and thus speaking ambiguously.


Oh for heaven's sake, one of the great beauties of the Game of Life is that
the meaning of state is simple and crystal clear; although in that game I
don't know the dividing line between microstates and macrostates so I just
call them states.

 even with reversible laws there is more than one way to get into a given
 macrostate


No. If there are 2 different states of the universe that could have
produced things as they are now then there is no way to decide between them
and history is unknowable (just as it is in the Game of Life) and the laws
of physics are not reversible.

 The entropy is defined not in terms of some vague notion of the number
 of ways the system could have gotten into its present microstate,


You mean its present macrostate. And I see nothing vague about it.


   but rather as the number of possible microstates the system might be in
 at this moment given that we only know the macrostate


We don't even know for a fact that some macroscopic objects, like Black
Holes for example, even contain microstates; in fact the present thinking
(a minority disagrees) is that probably they don't and a Black Hole can be
completely described by just 3 numbers, its mass, spin, and electric
charge. A Black Hole contains enormous entropy because there are a
gargantuan number of ways it could have been formed, but if you know those
3 numbers then you know all there is to know about a particular Black Hole.
And in the real world only 2 numbers are important because the electric
charge is always zero.

 For example, suppose we consider a very small 2x2 board with only 4 cells
 [...]


What are the laws of physics in this new game? A 2x2 board is MUCH too
small for the traditional rules of the Game of Life to be applicable.

 And if the macrostate is 0 black:4 white there's only one possible
 microstate (same for 4 black:0 white), so this is the lowest possible
 entropy


I don't know about this new game of yours because I don't know what the
rules are but in the Game of Life a solid block of nothing but active cells
would be in the lowest possible entropy state because the fewest previous
states could have produced it. Actually I should have said the lowest
impossible entropy state because NO previous state could have produced it,
zero.

A solid block of nothing but dead cells would have the highest entropy
because more previous states than any other could have produced it, and
entropy is the logarithm of the number of those states.

 If it starts out in a macrostate of maximum entropy [...]


Then nothing the laws of physics do to it can increase it's entropy
regardless of what those laws 

Re: What are wavefunctions?

2014-01-14 Thread John Clark
On Sun, Jan 12, 2014 at 6:41 PM, LizR lizj...@gmail.com wrote:


  Retro-causality (time symmetry is a better term) only exists at the
 quantum level.


  Why? Where is the dividing line? And with a Schrodinger's Cat type
 device a quantum event can easily be magnified to a macro-event as large as
 desired, you could connect it up to an H-bomb.


  The dividing line appears to be roughly where decoherence occurs.
 Basically anything above a single quantum entity engaged in a carefully
 controlled interaction is liable to get its time symmetric properties
 washed out by interactions with other particles


The nucleus of an atom is tiny even by atomic standards so it is certainly
at the quantum level, and in its natural state of existing inside a huge
chunk of irregular gyrating matter this tiny thing is constantly subject to
the slings and arrows of outrageous fortune from an astronomical number of
other clumsy atoms; and yet the half life of Bismuth 209 is 1.9 * 10^19
years. Why?

 It's just a fact, if time were symmetrical then you'd be just as good at
 predicting the future as you are at remembering the past, so you'd know the
 outcome of an experiment before you performed it just as well as you
 remember setting up the apparatus. But this is not the way things are
 because the second law exists. And the second law exists because of low
 entropy initial conditions. And I don't know why there were low entropy
 initial conditions.


  OK. So the above statement of yours about predicting the future is still
 false,


Yes it's false, I don't think this will come as a great news flash but the
truth is we're not as good at predicting the future as we are at
remembering the past. And the reason we're not is that time is not
symmetrical.

 To recap briefly -- the laws of physics are time symmetrical,


Yes, the fundamental laws of physics, the ones we know anyway, seem to be
time symmetrical. But that doesn't mean that time is symmetrical.

 and most particle interactions are constrained by boundary conditions.


Yes, and that is why time is NOT symmetrical.

  John K Clark

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Re: What are wavefunctions?

2014-01-14 Thread meekerdb

On 1/14/2014 8:33 AM, John Clark wrote:


  but rather as the number of possible microstates the system might be in 
at this
moment given that we only know the macrostate


We don't even know for a fact that some macroscopic objects, like Black Holes for 
example, even contain microstates; in fact the present thinking (a minority disagrees) 
is that probably they don't and a Black Hole can be completely described by just 3 
numbers, its mass, spin, and electric charge. A Black Hole contains enormous entropy 
because there are a gargantuan number of ways it could have been formed, but if you know 
those 3 numbers then you know all there is to know about a particular Black Hole. And in 
the real world only 2 numbers are important because the electric charge is always zero.


 For example, suppose we consider a very small 2x2 board with only 4 cells 
[...]


What are the laws of physics in this new game? A 2x2 board is MUCH too small for the 
traditional rules of the Game of Life to be applicable.


 And if the macrostate is 0 black:4 white there's only one possible 
microstate
(same for 4 black:0 white), so this is the lowest possible entropy


I don't know about this new game of yours because I don't know what the rules are but in 
the Game of Life a solid block of nothing but active cells would be in the lowest 
possible entropy state because the fewest previous states could have produced it. 
Actually I should have said the lowest impossible entropy state because NO previous 
state could have produced it, zero.


A solid block of nothing but dead cells would have the highest entropy because more 
previous states than any other could have produced it, and entropy is the logarithm of 
the number of those states.


You seem to have a non-standard view of entropy in statistical mechanics.  It is NOT the 
log of the number of ways a macro-state could form.  That would be ambiguous in any case 
(do different order of events count as different ways?...different paths to the events?).  
The entropy is the log of the number of micro-states consistent with the macro-state.  A 
black hole has entropy because it has a temperature, which implies that it has 
micro-states.  And the relationship between energy and temperature implies that the number 
of micro-states is the event horizon area measured in Planck units.  To say it only has 
mass, charge, and angular momentum is just to give a classical macro-state description, 
like saying gas in a vessel just has pressure, temperature, and volume.


Brent

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Re: What are wavefunctions?

2014-01-14 Thread LizR
On 15 January 2014 05:33, John Clark johnkcl...@gmail.com wrote:

 On Sun, Jan 12, 2014 at 1:22 PM, Jesse Mazer laserma...@gmail.com wrote:

  We know better than to think classical physics represents an exact
 description of our universe, but it certainly describes a logically
 possible mathematical universe


 Maybe but we don't know that with certainty, if we ever find a Theory of
 Everything we might find that classical physics is logically self
 contradictory.


We already know that it may contain singularities, which could be
considered at least physically problematical if not downright logically
inconsistent (especially by people who don't think anything real can be
infinite). Of course GR fails on that basis too.

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Re: What are wavefunctions?

2014-01-14 Thread LizR
On 15 January 2014 06:11, John Clark johnkcl...@gmail.com wrote:

 On Sun, Jan 12, 2014 at 6:41 PM, LizR lizj...@gmail.com wrote:


   Retro-causality (time symmetry is a better term) only exists at
 the quantum level.


  Why? Where is the dividing line? And with a Schrodinger's Cat type
 device a quantum event can easily be magnified to a macro-event as large as
 desired, you could connect it up to an H-bomb.


  The dividing line appears to be roughly where decoherence occurs.
 Basically anything above a single quantum entity engaged in a carefully
 controlled interaction is liable to get its time symmetric properties
 washed out by interactions with other particles


 The nucleus of an atom is tiny even by atomic standards so it is certainly
 at the quantum level, and in its natural state of existing inside a huge
 chunk of irregular gyrating matter this tiny thing is constantly subject to
 the slings and arrows of outrageous fortune from an astronomical number
 of other clumsy atoms; and yet the half life of Bismuth 209 is 1.9 * 10^19
 years. Why?


Because that's how long it takes for the relevant particles to get over the
potential barrier. But this is irrelevant. Atomic nuclei are (probably)
already on the wrong side of the entropy fence in any case. They're bound
states which can only occur under certain special cirumstances, namely when
the universe expands and cools enough to allow them to form. And atomic
nuclei haven't been used to violate Bell's inequality as far as I know.

  It's just a fact, if time were symmetrical then you'd be just as good
 at predicting the future as you are at remembering the past, so you'd know
 the outcome of an experiment before you performed it just as well as you
 remember setting up the apparatus. But this is not the way things are
 because the second law exists. And the second law exists because of low
 entropy initial conditions. And I don't know why there were low entropy
 initial conditions.


  OK. So the above statement of yours about predicting the future is still
 false,


Yes it's false, I don't think this will come as a great news flash but the
 truth is we're not as good at predicting the future as we are at
 remembering the past. And the reason we're not is that time is not
 symmetrical.


Except below the level of coarse graining at which entropy operates, that
is correct. And I never claimed otherwise. As I keep saying, I'm only
claiming this is relevant in special circumstances like EPR experiments.


  To recap briefly -- the laws of physics are time symmetrical,


 Yes, the fundamental laws of physics, the ones we know anyway, seem to be
 time symmetrical. But that doesn't mean that time is symmetrical.


...is just words. Stop nitpicking. If the laws of physics are time
symmetrical, that has a potential influence on EPR experiments.


  and most particle interactions are constrained by boundary conditions.


 Yes, and that is why time is NOT symmetrical.


Stop playing with words. The time symmetry of fundamental physics is there,
so it's perfectly valid to say time is symmetrical below the level of
coarse graining needed to derive the 2nd law, and asymmetrical above it.
(That's virtually a simple restatement of Boltzmann's H-theorem for
dummies.) The point is that symmetrical time may become apparent in EPR
setups. You haven't yet given even a suggestion of a reason why it
wouldn't, just a load of hand waving about stuff that is IRRELEVANT to EPR
experiments, which are carefully prepared to avoid all the influences
you've mentioned.

Now how about discussing what I've actually claimed, that time symmetry of
physics could account for the special situation which has to be created to
obtain EPR results?

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Re: What are wavefunctions?

2014-01-14 Thread LizR
Sorry, I realise that last sentence could be misconstrued by someone who's
being very nitpicky and looking for irrelevant loopholes to argue about, so
let's try again.

Now how about discussing what I've actually claimed, that the time symmetry
of fundamental physics could account for the results obtained in EPR
experiments?



On 15 January 2014 10:01, LizR lizj...@gmail.com wrote:

 On 15 January 2014 06:11, John Clark johnkcl...@gmail.com wrote:

 On Sun, Jan 12, 2014 at 6:41 PM, LizR lizj...@gmail.com wrote:


   Retro-causality (time symmetry is a better term) only exists at
 the quantum level.


  Why? Where is the dividing line? And with a Schrodinger's Cat type
 device a quantum event can easily be magnified to a macro-event as large as
 desired, you could connect it up to an H-bomb.


  The dividing line appears to be roughly where decoherence occurs.
 Basically anything above a single quantum entity engaged in a carefully
 controlled interaction is liable to get its time symmetric properties
 washed out by interactions with other particles


 The nucleus of an atom is tiny even by atomic standards so it is
 certainly at the quantum level, and in its natural state of existing inside
 a huge chunk of irregular gyrating matter this tiny thing is constantly
 subject to the slings and arrows of outrageous fortune from an
 astronomical number of other clumsy atoms; and yet the half life of Bismuth
 209 is 1.9 * 10^19 years. Why?


 Because that's how long it takes for the relevant particles to get over
 the potential barrier. But this is irrelevant. Atomic nuclei are (probably)
 already on the wrong side of the entropy fence in any case. They're bound
 states which can only occur under certain special cirumstances, namely when
 the universe expands and cools enough to allow them to form. And atomic
 nuclei haven't been used to violate Bell's inequality as far as I know.


   It's just a fact, if time were symmetrical then you'd be just as good
 at predicting the future as you are at remembering the past, so you'd know
 the outcome of an experiment before you performed it just as well as you
 remember setting up the apparatus. But this is not the way things are
 because the second law exists. And the second law exists because of low
 entropy initial conditions. And I don't know why there were low entropy
 initial conditions.


  OK. So the above statement of yours about predicting the future is
 still false,


 Yes it's false, I don't think this will come as a great news flash but the
 truth is we're not as good at predicting the future as we are at
 remembering the past. And the reason we're not is that time is not
 symmetrical.


 Except below the level of coarse graining at which entropy operates, that
 is correct. And I never claimed otherwise. As I keep saying, I'm only
 claiming this is relevant in special circumstances like EPR experiments.


  To recap briefly -- the laws of physics are time symmetrical,


 Yes, the fundamental laws of physics, the ones we know anyway, seem to be
 time symmetrical. But that doesn't mean that time is symmetrical.


 ...is just words. Stop nitpicking. If the laws of physics are time
 symmetrical, that has a potential influence on EPR experiments.


  and most particle interactions are constrained by boundary conditions.


 Yes, and that is why time is NOT symmetrical.


 Stop playing with words. The time symmetry of fundamental physics is
 there, so it's perfectly valid to say time is symmetrical below the level
 of coarse graining needed to derive the 2nd law, and asymmetrical above it.
 (That's virtually a simple restatement of Boltzmann's H-theorem for
 dummies.) The point is that symmetrical time may become apparent in EPR
 setups. You haven't yet given even a suggestion of a reason why it
 wouldn't, just a load of hand waving about stuff that is IRRELEVANT to EPR
 experiments, which are carefully prepared to avoid all the influences
 you've mentioned.

 Now how about discussing what I've actually claimed, that time symmetry of
 physics could account for the special situation which has to be created to
 obtain EPR results?



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Re: What are wavefunctions?

2014-01-12 Thread John Clark
On Fri, Jan 10, 2014 at 2:23 PM, Jesse Mazer laserma...@gmail.com wrot


  In classical physics there is no limit in principle to your knowledge of
 the microstate.


Yes, 150 years ago every physicist alive thought that, today we know better.


  And in quantum physics, there is nothing in principle preventing you
 from determining an exact quantum state for a system; only if you believe
 in some hidden-variables theory


And if you believe in some hidden-variable theory, ANY hidden-variable
theory, then you know that if things are realistic AND local then Bell's
inequality can NEVER be violated; and that would be true in every corner of
the multiverse provided that basic logic and arithmetic  is as true there
as here.  But experiment has shown unequivocally that Bell's inequality IS
violated. So you tell me, what conclusions can a logical person can draw
from that?


  like a theory that says that particles have precise position and
 momentum at all times, even though you can't measure them both
 simultaneously


If things have properties, like position and momentum, even if they are not
observed and even if they can't be observed in principle, then that would
be a realistic theory. If such a theory was also local you would know it is
wrong, that is to say it would conflict with the observed facts.


  Do you think my Toroidal Game of Life (a finite grid of cells with the
 edges identified, giving it the topology of a torus) is a mathematically
 well-defined possible universe?


 Yes.

  Do you disagree that starting from a randomly-chosen initial state which
 is likely to have something close to a 50:50 ratio of black to white
 squares, the board is likely to evolve to a state dominated by white
 squares, which would have lower entropy if we define macrostates in terms
 of the black:white ratio?


 You said it yourself, the rules of the Game of Life are NOT reversible,
that means there is more than one way for something to get into a given
state. And the present entropy of a system is defined by Boltzman as the
logarithm of the number of ways the system could have gotten into the state
it's in now, therefore every application of one of the fundamental rules of
physics in the Game of Life universe can only increase entropy.

  The 2nd law is not restricted to initial conditions of very low
 entropy, it says that if the entropy is anything lower than the maximum it
 will statistically tend to increase, and if the entropy is at the maximum
 it is statistically more likely to stay at that value than to drop to any
 specific lower value.


If the universe started out in a state of maximum entropy then any change
in it, that is to say any application of one of the fundamental laws of
physics will with certainty DECREASE that entropy.  And If the universe
started out in a state of ALMOST maximum entropy then any application of
one of the fundamental laws of physics will PROBABLY decrease that entropy.

  If the initial conditions deviated from maximum entropy even slightly,
 the second law says that an increase in entropy should be more likely than
 a decrease.

That would depend on initial conditions, just how slight the slight
deviation from maximum entropy was.


   Well... you can make a Turing Machine from the Game of Life. And
 according to the Bekenstein Bound



  The Bekenstein Bound is itself just a property of the particular laws of
 physics in our universe,


 This must be one of the few places where people talk about things that
just apply to our universe.


  no one claims it would apply to all logically possible mathematical
 universes, so how is it relevant to this discussion about whether the 2nd
 law would apply to all such possible universes?


 That wasn't what I was responding to. You said:

since even though it's possible our universe could be a cellular
automaton, I think we can be pretty confident it's not a 2-dimensional
cellular automaton like the Game of Life!

 And I gave reasons why I am not pretty confident

 So the rules of the Game of Life apply to some of the cells in the grid
 but do not apply to others. What rules govern which cells must obey the
 rules and which cells can ignore the rules, that is to say who is allowed
 to ignore the laws of physics in that universe?


  No, they apply to all squares in the ideal platonic infinite board whose
 behavior you want to deduce,


Then ratios become meaningless.

 but there is no need to actually *simulate* any of the squares outside
 the region containing black squares, because you know by the rules
 governing the ideal platonic infinite board that those squares will stay
 all-white as long as long as they are not neighbors with any black square


I think you've got your colors backward because a solid block of active
cells does not stay a solid block. But never mind the point is that the
pattern of active cells is constantly expanding and shrinking in a
unpredictable way (that is to say the only way to know what it will do is

Re: What are wavefunctions?

2014-01-12 Thread John Clark
On Fri, Jan 10, 2014 at 4:47 PM, LizR lizj...@gmail.com wrote:

 Retro-causality (time symmetry is a better term) only exists at the
 quantum level.


Why? Where is the dividing line? And with a Schrodinger's Cat type device a
quantum event can easily be magnified to a macro-event as large as desired,
you could connect it up to an H-bomb.

 The laws of physics are time-symmetric, but constrained by boundary
 conditions.


And that is exactly what I've been saying over and over, and that is why
the second law is almost always true and that is why time has a direction.

 There is a very influential boundary condition in what we call the past,
 namely the Big Bang, plus less influential ones in the future,


Exactly.

 And by the way, if time is symmetrical then there is no point in ever
 actually performing an experiment because you would remember the future as
 clearly as you remember the past, so you would already remember the outcome
 of the experiment just as clearly as you remember setting up the
 experimental apparatus.


 I assume you're not so stupid as to think that's what I've been claiming,
 so I can only assume this is a deliberate attempt at mockery,


Yes sometimes I mock people but I promise you that was not my aim this
time. It's just a fact, if time were symmetrical then you'd be just as good
at predicting the future as you are at remembering the past, so you'd know
the outcome of an experiment before you performed it just as well as you
remember setting up the apparatus. But this is not the way things are
because the second law exists. And the second law exists because of low
entropy initial conditions. And I don't know why there were low entropy
initial conditions.

  John K Clark

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Re: What are wavefunctions?

2014-01-12 Thread Bruno Marchal


On 12 Jan 2014, at 16:53, John Clark wrote:



On Fri, Jan 10, 2014 at 2:23 PM, Jesse Mazer laserma...@gmail.com  
wrot


 In classical physics there is no limit in principle to your  
knowledge of the microstate.


Yes, 150 years ago every physicist alive thought that, today we know  
better.


 And in quantum physics, there is nothing in principle preventing  
you from determining an exact quantum state for a system; only if  
you believe in some hidden-variables theory


And if you believe in some hidden-variable theory, ANY hidden- 
variable theory, then you know that if things are realistic AND  
local then Bell's inequality can NEVER be violated; and that would  
be true in every corner of the multiverse provided that basic logic  
and arithmetic  is as true there as here.  But experiment has shown  
unequivocally that Bell's inequality IS violated.


You keep saying this, but that is incorrect. The experiments have just  
shown that the Bell's inequality are violated in our universe,  
assuming that the outcomes of our experiments are definite, which they  
are not in the multiverse. Those experiments show nothing about our  
multiverse. The experiment are supposed to give definite outcomes, not  
the never collapsing superposed entanglement described in the big  
picture of the multiverse.
Read Deutsch and Hayden's paper, or Tipler's one, of just try to  
conceive an experimental set up showing a quantum violation of Bell's  
inequality in the many-world picture (if that can mean anything).  
Others gave links and papers.


MW is realist on all outcomes. The wave never collapse, which already  
suggest no action at a distance, but when you do the math, like  
Tipler, or Deustch and Hayden, (using the FPI, though, but restricted  
to the quantum computations, like Everett), you can see that nothing  
non local ever occurs.
Bell uses realism in some of his context, to say that there is only  
one (real) outcome, which is basically the contrary of the MW theory.


Bruno




So you tell me, what conclusions can a logical person can draw from  
that?


 like a theory that says that particles have precise position and  
momentum at all times, even though you can't measure them both  
simultaneously


If things have properties, like position and momentum, even if they  
are not observed and even if they can't be observed in principle,  
then that would be a realistic theory. If such a theory was also  
local you would know it is wrong, that is to say it would conflict  
with the observed facts.


 Do you think my Toroidal Game of Life (a finite grid of cells  
with the edges identified, giving it the topology of a torus) is a  
mathematically well-defined possible universe?


Yes.

 Do you disagree that starting from a randomly-chosen initial state  
which is likely to have something close to a 50:50 ratio of black to  
white squares, the board is likely to evolve to a state dominated by  
white squares, which would have lower entropy if we define  
macrostates in terms of the black:white ratio?


You said it yourself, the rules of the Game of Life are NOT  
reversible, that means there is more than one way for something to  
get into a given state. And the present entropy of a system is  
defined by Boltzman as the logarithm of the number of ways the  
system could have gotten into the state it's in now, therefore every  
application of one of the fundamental rules of physics in the Game  
of Life universe can only increase entropy.


 The 2nd law is not restricted to initial conditions of very low  
entropy, it says that if the entropy is anything lower than the  
maximum it will statistically tend to increase, and if the entropy  
is at the maximum it is statistically more likely to stay at that  
value than to drop to any specific lower value.


If the universe started out in a state of maximum entropy then any  
change in it, that is to say any application of one of the  
fundamental laws of physics will with certainty DECREASE that  
entropy.  And If the universe started out in a state of ALMOST  
maximum entropy then any application of one of the fundamental laws  
of physics will PROBABLY decrease that entropy.
 If the initial conditions deviated from maximum entropy even  
slightly, the second law says that an increase in entropy should be  
more likely than a decrease.


That would depend on initial conditions, just how slight the slight  
deviation from maximum entropy was.


 Well... you can make a Turing Machine from the Game of Life. And  
according to the Bekenstein Bound


 The Bekenstein Bound is itself just a property of the particular  
laws of physics in our universe,


This must be one of the few places where people talk about things  
that just apply to our universe.


 no one claims it would apply to all logically possible  
mathematical universes, so how is it relevant to this discussion  
about whether the 2nd law would apply to all such possible universes?


That wasn't what I 

Re: What are wavefunctions?

2014-01-12 Thread John Clark
On Fri, Jan 10, 2014 at 9:06 PM, meekerdb meeke...@verizon.net wrote:

 I'm not sure what time is symmetrical means to you.


The term is self evident.

 It's the equations of dynamical evolution that are t-symmetric in physics


Yes, time symmetrical laws of physics would usually mean that time was
symmetrical too, but not under very unusual initial conditions, like a
state of very low entropy.

 then retro-causality exists, so how can realism hold? How can the
 outcome of a coin flip today have a definite value independent of the
 observer if next year or next millennium someone can cause a change in
 today's coin flip?



  If the coin flip today had a definite outcome


Then things would be realistic.

why do suppose some one the future could simply choose it to be a different
 outcome?


Because if time were symmetrical then retro-causality would be just as
common as forward-causality and things would not be realistic.

 free will?


Cannot comment, don't know what ASCII sequence free will means.

 So you think realism would have no meaning in Laplace's deterministic
 universe?


Not at all, if things were deterministic then their values would exist
regardless of if somebody was observing them, or even if he could.

 And by the way, if time is symmetrical then there is no point in ever
 actually performing an experiment because you would remember the future as
 clearly as you remember the past, so you would already remember the outcome
 of the experiment just as clearly as you remember setting up the
 experimental apparatus.


  Not if time is symmetrical


No,*only* if time is symmetrical.

  dynamical equations are t-symmetric and memory depends on the state of
 a lot of particles in your brain so that the 2nd law applies.


If the 2nd law applies then time is not symmetrical because it says that
something (entropy) gets larger in one direction than it does in the other,
and that is lopsided.

 John K Clark

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Re: What are wavefunctions?

2014-01-12 Thread Jesse Mazer
On Sun, Jan 12, 2014 at 10:53 AM, John Clark johnkcl...@gmail.com wrote:


 On Fri, Jan 10, 2014 at 2:23 PM, Jesse Mazer laserma...@gmail.com wrot


  In classical physics there is no limit in principle to your knowledge
 of the microstate.


 Yes, 150 years ago every physicist alive thought that, today we know
 better.


We know better than to think classical physics represents an exact
description of our universe, but it certainly describes a logically
possible mathematical universe (note that in the previous paragraph of that
message of mine you are replying to, I said Liouville's theorem would be
precisely true in a possible universe where the laws of classical physics
hold exactly...for reference, that message is at
https://groups.google.com/d/msg/everything-list/hJ9bNWqoAzI/73DulLV7iyEJ )




  And in quantum physics, there is nothing in principle preventing you
 from determining an exact quantum state for a system; only if you believe
 in some hidden-variables theory


 And if you believe in some hidden-variable theory, ANY hidden-variable
 theory, then you know that if things are realistic AND local then Bell's
 inequality can NEVER be violated; and that would be true in every corner of
 the multiverse provided that basic logic and arithmetic  is as true there
 as here.  But experiment has shown unequivocally that Bell's inequality IS
 violated. So you tell me, what conclusions can a logical person can draw
 from that?



It tells us that either we must use a nonlocal hidden variables
interpretation like Bohmian mechanics, or that hidden variables are wrong.
Did you understand that in the sentence above that you quoted, I was saying
that there is nothing in principle preventing you from determining an
exact quantum state for a system in the case that the conjecture of hidden
variables is FALSE, not in the case that it's true? If there are no hidden
variables, then you can in principle perform an exhaustive measurement on a
system that will give you its exact state vector in Hilbert space, putting
it in a pure state rather than a mixed state. So, this contradicts your
claim that the laws of physics insist that you will *always* be uncertain
about the microstates--a pure quantum state *is* a microstate in quantum
physics without hidden variables, a macrostate would be a mixed state.





  Do you disagree that starting from a randomly-chosen initial state which
 is likely to have something close to a 50:50 ratio of black to white
 squares, the board is likely to evolve to a state dominated by white
 squares, which would have lower entropy if we define macrostates in terms
 of the black:white ratio?


 You said it yourself, the rules of the Game of Life are NOT reversible,
 that means there is more than one way for something to get into a given
 state. And the present entropy of a system is defined by Boltzman as the
 logarithm of the number of ways the system could have gotten into the state
 it's in now, therefore every application of one of the fundamental rules of
 physics in the Game of Life universe can only increase entropy.



You are failing to specify whether you mean state to refer to microstate
or macrostate and thus speaking ambiguously. The fact that the rules of the
Game of Life are not reversible means that there is more than one way for
something to get into a given microstate (even with reversible laws there
is more than one way to get into a given macrostate). The entropy is
defined not in terms of some vague notion of the number of ways the system
could have gotten into its present microstate, but rather as the number of
possible microstates the system might be in at this moment given that we
only know the macrostate it's in at this moment. If we define macrostates
for the Toroidal Game of Life in terms of the ratio of black to white
squares, then the entropy of a given macrostate has nothing to do with
looking at the board's possible states in the past, it's just a question of
looking at the number of possible precise patterns of black and white
squares that the board might have on the *current* time-increment that
would give it that ratio of black:white on the current time-increment. For
example, suppose we consider a very small 2x2 board with only 4 cells, and
I use 0s to represent white cells and 1s to represent black cells. Then if
the current macrostate is 2 black:2 white, the number of possible
microstates would be 6, shown below:

11
00

10
10

10
01

01
10

01
01

00
11

If the macrostate were 1 black:3 white there would be 4 possible
microstates (and same for 3 black:1 white), so this macrostate has a
lower entropy:

10
00

01
00

00
10

00
01

And if the macrostate is 0 black:4 white there's only one possible
microstate (same for 4 black:0 white), so this is the lowest possible
entropy for a macrostate:

00
00

It's not hard to see why this pattern would continue to hold for larger
boards--macrostates with a ratio that's closer to 1:1 will have a higher
entropy than 

Re: What are wavefunctions?

2014-01-12 Thread meekerdb

On 1/12/2014 8:20 AM, John Clark wrote:

On Fri, Jan 10, 2014 at 4:47 PM, LizR lizj...@gmail.com 
mailto:lizj...@gmail.com wrote:

 Retro-causality (time symmetry is a better term) only exists at the 
quantum level.


Why? Where is the dividing line? And with a Schrodinger's Cat type device a quantum 
event can easily be magnified to a macro-event as large as desired, you could connect it 
up to an H-bomb.


That's a good question.  But I think it has a good answer.  The quantum level really 
means isolated from the general entropy increase of the universe.  The Bucky Ball 
Young's slit experiment exemplifies this.  If the bucky balls are hot enough to radiate 
photons that will provide which way information, the interference pattern doesn't 
appear.  In the t-symmetry model this means the paths don't interact with the rest of 
universe.  If you tried to send a message back in time via the zig-zag path it would 
require an interaction between the wave-function and your macroscopic message forming and 
environmentally decohered instruments.


Brent

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Re: What are wavefunctions?

2014-01-12 Thread Jesse Mazer
On Sun, Jan 12, 2014 at 1:22 PM, Jesse Mazer laserma...@gmail.com wrote:


 The entropy is defined not in terms of some vague notion of the number of
 ways the system could have gotten into its present microstate, but rather
 as the number of possible microstates the system might be in at this moment
 given that we only know the macrostate it's in at this moment.


Minor correction, I meant to say that the entropy is defined in terms of
the number of microstates associated with the given macrostate--it isn't
defined as the number of microstates itself, but rather the logarithm of
that number (times Boltzmann's constant, if we're talking physical entropy
rather than informational).

Jesse

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Re: What are wavefunctions?

2014-01-12 Thread LizR
On 13 January 2014 05:20, John Clark johnkcl...@gmail.com wrote:

 On Fri, Jan 10, 2014 at 4:47 PM, LizR lizj...@gmail.com wrote:

  Retro-causality (time symmetry is a better term) only exists at the
 quantum level.


 Why? Where is the dividing line? And with a Schrodinger's Cat type device
 a quantum event can easily be magnified to a macro-event as large as
 desired, you could connect it up to an H-bomb.


The dividing line appears to be roughly where decoherence occurs. Basically
anything above a single quantum entity engaged in a carefully controlled
interaction is liable to get its time symmetric properties washed out by
interactions with other particles. I'm not sure exactly where the dividing
line is, but once you get above the scale of coarse-graining at which the
entropy gradient becomes manifest, you are going to lose any easily
measurable consequences of time symmetry. Only in carefully controlled
situations (like EPR experiments) can we remove the effects of influences
from the rest of the universe to a great enough extent that we can see
time-symmetry operating in a detectable manner (to, for example, violate
Bell's inequality, at least if Bell is to be believed).


  The laws of physics are time-symmetric, but constrained by boundary
 conditions.


 And that is exactly what I've been saying over and over, and that is why
 the second law is almost always true and that is why time has a direction.


Yes, I've been saying this over and over, too. So we agree. The second law
is almost always true, and only in special cases like EPR experiments can
we easily see the effects of time symmetry -- even though we *know* most of
the laws of physics are time-symmetric (insofar as we know anything, of
course).


  There is a very influential boundary condition in what we call the past,
 namely the Big Bang, plus less influential ones in the future,


 Exactly.


This is why it's so hard to get our heads around the consequences of time
symmetry.


   And by the way, if time is symmetrical then there is no point in ever
 actually performing an experiment because you would remember the future as
 clearly as you remember the past, so you would already remember the outcome
 of the experiment just as clearly as you remember setting up the
 experimental apparatus.


 I assume you're not so stupid as to think that's what I've been
 claiming, so I can only assume this is a deliberate attempt at mockery,


 Yes sometimes I mock people but I promise you that was not my aim this
 time. It's just a fact, if time were symmetrical then you'd be just as good
 at predicting the future as you are at remembering the past, so you'd know
 the outcome of an experiment before you performed it just as well as you
 remember setting up the apparatus. But this is not the way things are
 because the second law exists. And the second law exists because of low
 entropy initial conditions. And I don't know why there were low entropy
 initial conditions.


OK. So the above statement of yours about predicting the future is still
false, and hopefully you now understand why. To recap briefly -- the laws
of physics are time symmetrical, and most particle interactions are
constrained by boundary conditions. Almost everything in the universe is
constrained by the boundary condition of the Big Bang (+ cosmic expansion).
This creates an entropy gradient (or rather what we perceive as one, as
Brent explained the entropy of a system doesn't change at the quantum
level, but we exist above the level of coarse graining at which the 2nd law
emerges). This prevents us measuring the results of any future experiments
that involve anything above the level of coarse-graining, i.e. above the
level of a few carefully prepared particles.

And since we don't use EPR type experiments for our memories, we can't
remember the future.

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Re: What are wavefunctions?

2014-01-10 Thread John Clark
On Thu, Jan 9, 2014  Jesse Mazer laserma...@gmail.com wrote:

I never claimed Liouville's theorem was a fundamental law of physics in
 itself,


Good, I agree.

 rather it is derivable as a mathematical consequence of certain features
 of the fundamental laws.


And of the initial conditions!

 Liouville's theorem is derived in deterministic classical mechanics.


Then Liouville's theorem can only be approximately true.


  It [Liouville's theorem] only becomes statistical if you interpret the
 original set of microstates as representing your own uncertainty


But that's the only way you can interpret it because the laws of physics
insist that you will *always* be uncertain about the microstates, all you
know are purely statistical things about the system, like its temperature
and pressure.

 This line of discussion got started because I was disputing your
 statement that we can derive the 2nd law in a *purely* logical way like
 2+2=5, with no need to invoke knowledge about the laws of physics that was
 based on observation. This would imply that *any* logically possible
 mathematical laws of nature would obey the 2nd law.


Yes, *any* logically possible mathematical law of nature must actually do
something, or it shouldn't be called a law. If the initial state of a
system is in a state of lowest possible entropy, and if one of those laws
goes to work on that state then the entropy of the system in that state
will NOT go down. And that is the second law of thermodynamics.

 If you did not mean to suggest that we can know a priori the 2nd law is
 true because it would be true in any logically possible universe whose
 behavior follows mathematical laws, please clarify.


That is exactly what I meant to suggest, provided that the initial
conditions were of very low entropy.

 But I thought you were talking about logically possible universes as
 well, not just our universe


If the initial conditions were of high entropy then applying a law of
physics to that mess would be just as likely to decrease its entropy as
increase it, therefore the second law would not be true and time would have
no arrow; in fact the very concept of time would have no meaning in that
universe.

 the very fact that you were willing to discuss the Game of Life suggested
 this, since even though it's possible our universe could be a cellular
 automaton, I think we can be pretty confident it's not a 2-dimensional
 cellular automaton like the Game of Life!


Well... you can make a Turing Machine from the Game of Life. And according
to the Bekenstein Bound the maximum amount of information that the laws of
physics allow you to store inside a sphere is NOT proportional to its 3D
volume as you might expect but is instead proportional to the sphere's 2D
surface area. So you could know all there is to know about what's going on
inside a sphere just by looking at its surface, this has led some to
propose what they call  The Holographic principle, the idea is that the
entire volume of our 3D universe is a projection from a 2D surface.

 Maybe they're right. As I've said I don't know what reality will turn out
to be but whatever it is it's going to be weird.

 Another alternative would be to imagine you do have an infinite grid,
 but with a starting state where there are only a finite pattern of black
 squares surrounded by an infinite number of white squares,


  So the ratio of white squares to black is a finite number divided by
 infinity.


 No, because I said that in this case the region of the grid being
 *simulated* could still be finite


So the rules of the Game of Life apply to some of the cells in the grid but
do not apply to others. What rules govern which cells must obey the rules
and which cells can ignore the rules, that is to say who is allowed to
ignore the laws of physics in that universe?

  John K Clark

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Re: What are wavefunctions?

2014-01-10 Thread John Clark
On Thu, Jan 9, 2014 at 5:38 PM, LizR lizj...@gmail.com wrote:

As a lot of people have now pointed out, physics can be local and relistic
 if time symmetry is valid.


If time is symmetrical then retro-causality exists, so how can realism
hold? How can the outcome of a coin flip today have a definite value
independent of the observer if next year or next millennium someone can
cause a change in today's coin flip? If realism holds under those
circumstances then the word realism has no meaning.

And by the way, if time is symmetrical then there is no point in ever
actually performing an experiment because you would remember the future as
clearly as you remember the past, so you would already remember the outcome
of the experiment just as clearly as you remember setting up the
experimental apparatus.

  John K Clark

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Re: What are wavefunctions?

2014-01-10 Thread Jesse Mazer
On Fri, Jan 10, 2014 at 12:20 PM, John Clark johnkcl...@gmail.com wrote:

 On Thu, Jan 9, 2014  Jesse Mazer laserma...@gmail.com wrote:

 I never claimed Liouville's theorem was a fundamental law of physics in
 itself,


 Good, I agree.

  rather it is derivable as a mathematical consequence of certain features
 of the fundamental laws.


 And of the initial conditions!


No, it doesn't depend on initial conditions. No matter what set of initial
microstates you choose at time T0, if you evolve each one forward to get a
new set of microstates at time T1, then the volume of phase space occupied
by the microstates at T0 will be precisely equal to the volume of phase
space occupied by the microstates at T1. Do you disagree?




  Liouville's theorem is derived in deterministic classical mechanics.


 Then Liouville's theorem can only be approximately true.


It'd be precisely true in a possible universe where the laws of classical
physics hold exactly. Of course in our universe they don't, but there is
apparently a quantum analogue of Liouville's theorem, though I don't
understand it as well--see
https://en.wikipedia.org/wiki/Liouville's_theorem_(Hamiltonian)#Quantum_Liouville_equation




  It [Liouville's theorem] only becomes statistical if you interpret the
 original set of microstates as representing your own uncertainty


 But that's the only way you can interpret it because the laws of physics
 insist that you will *always* be uncertain about the microstates, all you
 know are purely statistical things about the system, like its temperature
 and pressure.


In classical physics there is no limit in principle to your knowledge of
the microstate. And in quantum physics, there is nothing in principle
preventing you from determining an exact quantum state for a system; only
if you believe in some hidden-variables theory (like a theory that says
that particles have precise position and momentum at all times, even though
you can't measure them both simultaneously) would this be
less-than-complete information about the microstate.



  This line of discussion got started because I was disputing your
 statement that we can derive the 2nd law in a *purely* logical way like
 2+2=5, with no need to invoke knowledge about the laws of physics that was
 based on observation. This would imply that *any* logically possible
 mathematical laws of nature would obey the 2nd law.


 Yes, *any* logically possible mathematical law of nature must actually do
 something, or it shouldn't be called a law. If the initial state of a
 system is in a state of lowest possible entropy, and if one of those laws
 goes to work on that state then the entropy of the system in that state
 will NOT go down. And that is the second law of thermodynamics.


Do you think my Toroidal Game of Life (a finite grid of cells with the
edges identified, giving it the topology of a torus) is a mathematically
well-defined possible universe? Do you disagree that starting from a
randomly-chosen initial state which is likely to have something close to a
50:50 ratio of black to white squares, the board is likely to evolve to a
state dominated by white squares, which would have lower entropy if we
define macrostates in terms of the black:white ratio?




  If you did not mean to suggest that we can know a priori the 2nd law is
 true because it would be true in any logically possible universe whose
 behavior follows mathematical laws, please clarify.


 That is exactly what I meant to suggest, provided that the initial
 conditions were of very low entropy.


The 2nd law is not restricted to initial conditions of very low entropy,
it says that if the entropy is anything lower than the maximum it will
statistically tend to increase, and if the entropy is at the maximum it is
statistically more likely to stay at that value than to drop to any
specific lower value.



   But I thought you were talking about logically possible universes as
 well, not just our universe


 If the initial conditions were of high entropy then applying a law of
 physics to that mess would be just as likely to decrease its entropy as
 increase it, therefore the second law would not be true and time would have
 no arrow; in fact the very concept of time would have no meaning in that
 universe.


If the initial conditions deviated from maximum entropy even slightly, the
second law says that an increase in entropy should be more likely than a
decrease. For example, suppose we have 10,000 gas atoms in a box with no
external forces acting on them, and we divide the box into two equal
halves, and choose an initial macrostate where 5,100 atoms are in one half
of the box and 4,900 atoms are in the other half. If the laws of physics
applied to this initial macrostate were such that the ratio of atoms in
each side was more likely to get *further* from 50:50 than 51:49 rather
than closer to 50:50, that would be a clear violation of the 2nd law. Do
you disagree?

If you agree with that, then it's 

Re: What are wavefunctions?

2014-01-10 Thread Jesse Mazer
On Fri, Jan 10, 2014 at 12:43 PM, John Clark johnkcl...@gmail.com wrote:

 On Thu, Jan 9, 2014 at 5:38 PM, LizR lizj...@gmail.com wrote:

 As a lot of people have now pointed out, physics can be local and
 relistic if time symmetry is valid.


 If time is symmetrical then retro-causality exists, so how can realism
 hold? How can the outcome of a coin flip today have a definite value
 independent of the observer if next year or next millennium someone can
 cause a change in today's coin flip? If realism holds under those
 circumstances then the word realism has no meaning.


There could be no change if the Novikov self-consistency principle holds
(see https://en.wikipedia.org/wiki/Novikov_self-consistency_principle ),
which is what physicists usually assume when analyzing theoretical
scenarios where time travel could be possible, like traversable wormholes
in general relativity. In this case the block time assumption holds, you
just have a fixed 4D spacetime where all cause-and-effect sequences are
already part of it, and any retrocausal influences must have been part of
history all along rather than changing history from one sequence of
events to an altered sequence.

Jesse

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Re: What are wavefunctions?

2014-01-10 Thread Jason Resch



On Jan 10, 2014, at 11:43 AM, John Clark johnkcl...@gmail.com wrote:


On Thu, Jan 9, 2014 at 5:38 PM, LizR lizj...@gmail.com wrote:

As a lot of people have now pointed out, physics can be local and  
relistic if time symmetry is valid.


If time is symmetrical then retro-causality exists, so how can  
realism hold? How can the outcome of a coin flip today have a  
definite value independent of the observer if next year or next  
millennium someone can cause a change in today's coin flip?


You are the obe who always says free will is meaningless. How can  
anyone change anything from how it would otherwise be if they and  
everything are ruled by the deterministic laws?


The block time view makes this more clear. We can no more change the  
future than change the present or the past.



If realism holds under those circumstances then the word realism  
has no meaning.


Do you think realism is valid in the block time view?




And by the way, if time is symmetrical then there is no point in  
ever actually performing an experiment because you would remember  
the future as clearly as you remember the past,


The second law of thermodynamics prohibits this, as I explained in  
recent posts.


Jason

so you would already remember the outcome of the experiment just as  
clearly as you remember setting up the experimental apparatus.


  John K Clark


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Re: What are wavefunctions?

2014-01-10 Thread LizR
On 11 January 2014 06:43, John Clark johnkcl...@gmail.com wrote:

 On Thu, Jan 9, 2014 at 5:38 PM, LizR lizj...@gmail.com wrote:

 As a lot of people have now pointed out, physics can be local and
 relistic if time symmetry is valid.


 If time is symmetrical then retro-causality exists, so how can realism
 hold? How can the outcome of a coin flip today have a definite value
 independent of the observer if next year or next millennium someone can
 cause a change in today's coin flip? If realism holds under those
 circumstances then the word realism has no meaning.


Retro-causality (time symmetry is a better term) only exists at the
quantum level. The laws of physics are time-symmetric, but constrained by
boundary conditions. There is a very influential boundary condition in what
we call the past, namely the Big Bang, plus less influential ones in the
future, like the settings of measuring apparatuses. At all scales except
that of individual quantum events, the pastward boundary condition washes
out any noticeable effects of time symmetry. (That's what it means when we
say that entropy increase involves coarse graining.)


 And by the way, if time is symmetrical then there is no point in ever
 actually performing an experiment because you would remember the future as
 clearly as you remember the past, so you would already remember the outcome
 of the experiment just as clearly as you remember setting up the
 experimental apparatus.


I assume you're not so stupid as to think that's what I've been claiming,
so I can only assume this is a deliberate attempt at mockery, directed at a
straw man as such attempts usually are. I had hoped for a better standard
of debate on this list.

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Re: What are wavefunctions?

2014-01-10 Thread LizR
On 11 January 2014 08:52, Jason Resch jasonre...@gmail.com wrote:

 On Jan 10, 2014, at 11:43 AM, John Clark johnkcl...@gmail.com wrote:

 On Thu, Jan 9, 2014 at 5:38 PM, LizR  lizj...@gmail.com
 lizj...@gmail.com wrote:

 As a lot of people have now pointed out, physics can be local and
 relistic if time symmetry is valid.


 If time is symmetrical then retro-causality exists, so how can realism
 hold? How can the outcome of a coin flip today have a definite value
 independent of the observer if next year or next millennium someone can
 cause a change in today's coin flip?


 You are the obe who always says free will is meaningless. How can anyone
 change anything from how it would otherwise be if they and everything are
 ruled by the deterministic laws?

 The block time view makes this more clear. We can no more change the
 future than change the present or the past.

 The simplest way to understand this is to consider the past. If you look
at the past, you see a perfect example of a block universe, with all the
causal links (in either time direction) embedded in it. Now you just have
to make the mental effort to extend that to the future, and to imagine that
we are embedded, just as King Harold is embedded in 1066. Harold thinks
that he is in a moving present but we can see his entire history. It's
all there.  Was he wrong? Yes, he was, we can see that now. Are we wrong?
Ask someone in the next year/day/minute...

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Re: What are wavefunctions?

2014-01-10 Thread meekerdb

On 1/10/2014 9:43 AM, John Clark wrote:

On Thu, Jan 9, 2014 at 5:38 PM, LizR lizj...@gmail.com 
mailto:lizj...@gmail.com wrote:

As a lot of people have now pointed out, physics can be local and relistic 
if time
symmetry is valid.


If time is symmetrical


I'm not sure what time is symmetrical means to you.  It's the equations of dynamical 
evolution that are t-symmetric in physics (both classical and quantum-sans-collapse).


then retro-causality exists, so how can realism hold? How can the outcome of a coin flip 
today have a definite value independent of the observer if next year or next millennium 
someone can cause a change in today's coin flip?


If the coin flip today had a definite outcome why do suppose some one the future could 
simply choose it to be a different outcome?...free will?



If realism holds under those circumstances then the word realism has no 
meaning.


So you think realism would have no meaning in Laplace's deterministic universe?



And by the way, if time is symmetrical then there is no point in ever actually 
performing an experiment because you would remember the future as clearly as you 
remember the past, so you would already remember the outcome of the experiment just as 
clearly as you remember setting up the experimental apparatus.


Not if time is symmetrical == dynamical equations are t-symmetric and memory depends 
on the state of a lot of particles in your brain so that the 2nd law applies.


Brent

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Re: What are wavefunctions?

2014-01-09 Thread Quentin Anciaux
2014/1/9 John Clark johnkcl...@gmail.com

 On Wed, Jan 8, 2014 at 1:42 PM, Bruno Marchal marc...@ulb.ac.be wrote:

  Well, read Bell.


 I have.

  It shows how QM violates his inequality.


 I know, I demonstrated exactly that on this very list using my own
 language. And Bell knew of course that his inequality was not consistent
 with Quantum Mechanics, what he didn't know at the time was if his
 inequality was consistent with reality or if Quantum Mechanics was. That
 question was answered experimentally a couple of decades after Bell's
 theoretical work and the winner was Quantum Mechanics; so now we know that
 at least one of the assumptions that Bell made (realism, locality, high
 school math works) must be wrong.

  but Bell's inequality IS violated.



 Experimentally,


 Huh? This is a physical idea not a mathematical one, how else could it be
 proven wrong other than experimentally?

  But when you look at the many branches, at once [...]


 Unfortunately my eyesight isn't good enough to allow me to look at many
 branches of the multiverse at once.

  to me, the Bell's inequality experimental violation is a quite strong
 evidence for MW, that is QM-without collapse.


 To me Bell's inequality experimental violation is a quite strong evidence
 that reality is not local or not realistic or not either. MWI is not local


As I said Liar Clark *even* when presented with evidences will continue
till his death to lie... what's the point to discuss with such a guy ?

Quentin


 so it could be correct, and emotionally it is my favorite interpretation,
 but logically I must admit that it is not the only interpretation that
 could be correct. Much as I dislike Copenhagen the fact is it's
 non-realistic so the violation of Bell's inequality is not rule it out. But
 Einstein's idea that things are realistic and local (and deterministic too
 although determinism was less important to Einstein than realism or
 locality) IS ruled out.

   John K Clark




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-- 
All those moments will be lost in time, like tears in rain. (Roy
Batty/Rutger Hauer)

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 2:34 PM, Jesse Mazer laserma...@gmail.com wrote:

I think you will find relatively few physicists who expect that any new
 fundamental theory like quantum gravity will fail to have these [time]
 symmetries


If so then time's arrow, that is to say time's asymmetry, is not the result
of the fundamental laws of physics but is a statistical effect that could
not be otherwise due to the nature of the initial conditions and the fact
that there are just more ways to be disorganized than organized.

 by far the most popular explanation for macroscopic arrows of time is
 that it's due to the low-entropy boundary condition at the Big Bang


And I have said exactly that approximately 6.02 * 10^23 times.

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 7:52 PM, meekerdb meeke...@verizon.net wrote:

  All the physicists I know regard the second law of thermodynamics as a
 statistical, not fundamental, law.


Exactly, and because statistics is based on pure logic and not on the
trendy physical theory of the day if you asked those same physicists what
idea is most likely to still seem valid to the scientific community in a
thousand or even a million years they would probably say the second law of
thermodynamics.

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 2:41 PM, Jesse Mazer laserma...@gmail.com wrote

 For example, in Life one could define macrostates in terms of the ratio
 of white to black cells [...]


In the Game of Life the number of black cells is always infinite, so I
don't see how you can do any ratios.

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 1:42 PM, Bruno Marchal marc...@ulb.ac.be wrote:

 Well, read Bell.


I have.

 It shows how QM violates his inequality.


I know, I demonstrated exactly that on this very list using my own
language. And Bell knew of course that his inequality was not consistent
with Quantum Mechanics, what he didn't know at the time was if his
inequality was consistent with reality or if Quantum Mechanics was. That
question was answered experimentally a couple of decades after Bell's
theoretical work and the winner was Quantum Mechanics; so now we know that
at least one of the assumptions that Bell made (realism, locality, high
school math works) must be wrong.

 but Bell's inequality IS violated.



Experimentally,


Huh? This is a physical idea not a mathematical one, how else could it be
proven wrong other than experimentally?

 But when you look at the many branches, at once [...]


Unfortunately my eyesight isn't good enough to allow me to look at many
branches of the multiverse at once.

 to me, the Bell's inequality experimental violation is a quite strong
 evidence for MW, that is QM-without collapse.


To me Bell's inequality experimental violation is a quite strong evidence
that reality is not local or not realistic or not either. MWI is not local
so it could be correct, and emotionally it is my favorite interpretation,
but logically I must admit that it is not the only interpretation that
could be correct. Much as I dislike Copenhagen the fact is it's
non-realistic so the violation of Bell's inequality is not rule it out. But
Einstein's idea that things are realistic and local (and deterministic too
although determinism was less important to Einstein than realism or
locality) IS ruled out.

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 6:59 PM, LizR lizj...@gmail.com wrote:

 I'm arguing that time is symmetric,


  Good luck winning that argument when nearly everything we observe,
 from cosmology to cooking, screams at us that time is NOT symmetric.


  Not at the quantum level,


If so then obviously the quantum level is not the end of the story.


  it was actually discovered before Bell died that there's a perfectly
 reasonable explanation for how his inequality can be violated that retains
 locality and realism.


  Baloney.


  If that's the best refutation you can come up with, John Bell and Huw
 Price have nothing to fear.


They have nothing to fear from me or the truth. If retro-causality exists
then things are not local and not realistic either, so that possibility has
not been ruled out experimentally. But the common sense view that most
people, including Einstein, had about reality, that things are realistic
and local, CAN be ruled out. And of all the people on the planet John Bell
would be the last to disagree that if his inequality is violated then
things are not local or not realistic or not either.

 John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Wed, Jan 8, 2014 at 7:11 PM, LizR lizj...@gmail.com wrote:

 The equations of Newtonian dynamics are time-symmetric,


I know.

 similarly for relativity both SR and GR -


I know

 and quantum mechanics is, too.


I know.

 The only thing in the entirety f physics that isn't based on time
 symmetric equations is thermodynamics,


That and the equations of cosmology. And astrophysics. And meteorology. And
[...]

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread Bruno Marchal


On 09 Jan 2014, at 17:53, John Clark wrote:

On Wed, Jan 8, 2014 at 1:42 PM, Bruno Marchal marc...@ulb.ac.be  
wrote:


 Well, read Bell.

I have.

 It shows how QM violates his inequality.

I know, I demonstrated exactly that on this very list using my own  
language. And Bell knew of course that his inequality was not  
consistent with Quantum Mechanics,


with Copenhagen QM.



what he didn't know at the time was if his inequality was consistent  
with reality or if Quantum Mechanics was. That question was answered  
experimentally a couple of decades after Bell's theoretical work and  
the winner was Quantum Mechanics;


Yes.



so now we know that at least one of the assumptions that Bell made  
(realism, locality, high school math works) must be wrong.


In Bell realism bears on the unique outcome. It is realism in  
Copenhagen QM. he does not address the question of locality in the non- 
collapse theory (which he does not like).







 but Bell's inequality IS violated.

Experimentally,

Huh? This is a physical idea not a mathematical one, how else could  
it be proven wrong other than experimentally?


Sometimes it is good to be redundant on what is important :)





 But when you look at the many branches, at once [...]

Unfortunately my eyesight isn't good enough to allow me to look at  
many branches of the multiverse at once.


There is a technic: do QM. Just look at the terms in the solution of  
shroedinger equation, involving yourself,  perhaps with Alice and Bob,  
etc.






 to me, the Bell's inequality experimental violation is a quite  
strong evidence for MW, that is QM-without collapse.


To me Bell's inequality experimental violation is a quite strong  
evidence that reality is not local


I am the one here who will tell you that 3p non locality is only a  
sound made by your lips and nothing else.


Einstein was skeptical of the collapse of the wave because it  
introduce non locality, and non covariance. I think he is right. 3p  
non locality is telepathy or spooky action at a distance. It does not  
make sense to me.






or not realistic or not either.






MWI is not local


Proof? The violation of Bell's inequality implies non locality for a  
realist interpretation of QM+collapse. When collapse never happens,  
all that occur comes from local interaction and interference,  
spreading at speed less than c.





so it could be correct, and emotionally it is my favorite  
interpretation, but logically I must admit that it is not the only  
interpretation that could be correct. Much as I dislike Copenhagen  
the fact is it's non-realistic so the violation of Bell's inequality  
is not rule it out. But Einstein's idea that things are realistic  
and local (and deterministic too although determinism was less  
important to Einstein than realism or locality) IS ruled out.


Proof?

Quantum indeterminacy and quantum non locality are pure first person  
plural illusion (subjective, first person) in Everett.


3p determinism was as much important than 3p locality for Einstein.  
God does not play dice. He will keep that idea all his life. This is  
well known.


There is few doubt, for me, that, like most cosmologist, he would have  
preferred many worlds than anything non deterministic or non local. I  
think (even more so after the reading of Jammer's book on Einstein's  
religion).


Bruno





  John K Clark





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http://iridia.ulb.ac.be/~marchal/



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Re: What are wavefunctions?

2014-01-09 Thread Bruno Marchal


On 09 Jan 2014, at 18:24, John Clark wrote:

On Wed, Jan 8, 2014 at 2:41 PM, Jesse Mazer laserma...@gmail.com  
wrote


 For example, in Life one could define macrostates in terms of the  
ratio of white to black cells [...]


In the Game of Life the number of black cells is always infinite,


Because you restrict yourself to finite pattern.  (Well, it is not a  
bad idea, to encode a state of mind, but that less sure for a universe  
of a god or something else).




so I don't see how you can do any ratios.


You can do local ratios, with suitable definition, and I guess that  
was Jesse meant.


Bruno





  John K Clark



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Re: What are wavefunctions?

2014-01-09 Thread Jesse Mazer
On Thu, Jan 9, 2014 at 12:58 PM, John Clark johnkcl...@gmail.com wrote:

 On Wed, Jan 8, 2014 at 7:11 PM, LizR lizj...@gmail.com wrote:

  The equations of Newtonian dynamics are time-symmetric,


 I know.

  similarly for relativity both SR and GR -


 I know

  and quantum mechanics is, too.


 I know.

  The only thing in the entirety f physics that isn't based on time
 symmetric equations is thermodynamics,


 That and the equations of cosmology. And astrophysics. And meteorology.
 And [...]
 http://groups.google.com/group/everything-list


What equations of cosmology are there besides the equations of general
relativity, used to model the entire universe? In general it's true that in
some cases scientists use separate equations derived from observation to
deal with large-scale phenomena, as in climate modeling. However, it is
always assumed that reductionism holds, that the behavior of any
large-scale system ultimately emerges statistically from the interaction of
all its basic parts evolving according to more fundamental laws (as has
been shown to be true of thermodynamic laws in statistical mechanics), even
if in some cases it may be too difficult in practice to derive the
higher-level equations from the fundamental ones (but it is possible for
other cases besides thermodynamics, for example the interactions of certain
molecules, normally the domain of chemistry, can be derived from basic
quantum rules alone, as with the model of interacting water molecules
discussed at http://www.udel.edu/PR/UDaily/2007/mar/water030207.html ). Do
you disagree with reductionism in this sense? Are you suggesting that any
equations governing higher-level systems are irreducible even in principle
to lower-level laws (plus initial conditions or other boundary conditions)?

Jesse

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Re: What are wavefunctions?

2014-01-09 Thread Jesse Mazer
On Thu, Jan 9, 2014 at 12:08 PM, John Clark johnkcl...@gmail.com wrote:




 On Wed, Jan 8, 2014 at 2:34 PM, Jesse Mazer laserma...@gmail.com wrote:

 I think you will find relatively few physicists who expect that any new
 fundamental theory like quantum gravity will fail to have these [time]
 symmetries


 If so then time's arrow, that is to say time's asymmetry, is not the
 result of the fundamental laws of physics but is a statistical effect that
 could not be otherwise due to the nature of the initial conditions and the
 fact that there are just more ways to be disorganized than organized.


But obviously if it's dependent on initial conditions then you can't derive
it from logic alone, since it's logically possible that the initial
conditions could have been different. And as I've said, there is also the
fact that if the laws of physics don't conserve phase space volume, the 2nd
law wouldn't hold either.





  by far the most popular explanation for macroscopic arrows of time is
 that it's due to the low-entropy boundary condition at the Big Bang


 And I have said exactly that approximately 6.02 * 10^23 times.


OK, but you hadn't said that to *me* before--there are a lot of posts on
this list, I don't read all of them.

Jesse

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Re: What are wavefunctions?

2014-01-09 Thread Jesse Mazer
On Thu, Jan 9, 2014 at 12:24 PM, John Clark johnkcl...@gmail.com wrote:

 On Wed, Jan 8, 2014 at 2:41 PM, Jesse Mazer laserma...@gmail.com wrote

  For example, in Life one could define macrostates in terms of the ratio
 of white to black cells [...]


 In the Game of Life the number of black cells is always infinite, so I
 don't see how you can do any ratios.

   John K Clark


Maybe that would be true for some ideal Platonic version of the Game of
Life on an infinite board, but any real-world implementation of a cellular
automaton involves a finite number of squares--usually this is done with a
periodic boundary condition, so squares on the left edge of the finite grid
are defined to be neighbors of squares on the right edge, and squares on
the top edge of the grid are defined to be neighbors of squares on the
bottom edge. Another alternative would be to imagine you do have an
infinite grid, but with a starting state where there are only a finite
pattern of black squares surrounded by an infinite number of white squares,
then you can expand the size of the simulated grid if the region of black
squares approaches its border, so that the grid always remains larger than
the region of black squares (you don't have to simulate regions beyond that
because any region that's all-white on a given time-step, and doesn't have
any black squares on its immediate border, will stay all-white on the next
time-step).

In either of these cases (though it's easier to analyze the periodic
example since the grid size remains constant), the ratio of black squares
to white squares on the simulated grid region at any given time is
well-defined, so one can use this ratio to define the macrostate. And since
the rules of the Game of Life aren't reversible, and many different initial
states end up either in an all-white end state or an end-state with mostly
white and a few blinking black shapes, I'm pretty sure this would be a case
where an entropy defined in terms of these macrostates would tend to
decrease from a randomly-chosen initial finite pattern of black squares. Do
you disagree? (even if you're not as confident as I am that this would be
true for the Game of Life, one could easily define less interesting
transition rules where this is obviously the case, like a transition rule
that says that only if a black square has a single black neighbor will it
remain white, in every other case the square will turn white--hopefully
you'd at least agree that in this case, entropy would tend to decrease from
a random initial state on a periodic grid).

Jesse

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Re: What are wavefunctions?

2014-01-09 Thread Jesse Mazer
On Thu, Jan 9, 2014 at 11:53 AM, John Clark johnkcl...@gmail.com wrote:

 On Wed, Jan 8, 2014 at 1:42 PM, Bruno Marchal marc...@ulb.ac.be

  to me, the Bell's inequality experimental violation is a quite strong
 evidence for MW, that is QM-without collapse.


 To me Bell's inequality experimental violation is a quite strong evidence
 that reality is not local or not realistic or not either. MWI is not local
 so it could be correct, and emotionally it is my favorite interpretation,
 but logically I must admit that it is not the only interpretation that
 could be correct.


Why do you say MWI is not local? Many physicists who advocate the MWI
would disagree, like David Deutsch:

http://arxiv.org/abs/1109.6223
http://arxiv.org/abs/quant-ph/9906007

This paper by Mark Rubin presents another defense of locality in the MWI:

http://arxiv.org/abs/quant-ph/0103079

In it he mentions some of the history of defenses of MWI locality:

In the Everett interpretation the nonlocal notion of reduction of the
wavefunction is eliminated, suggesting that questions of the locality of
quantum mechanics might indeed be more easily addressed. On the other hand,
while wavefunctions do not suffer reduction in the Everett interpretation,
nonlocality nevertheless remains present in many accounts of this
formulation. In DeWitt’s (1970) often-quoted description, for example,
“every quantum transition taking place on every star, in every galaxy, in
every remote corner of the universe is splitting our local world on earth
into myriads of copies of itself.” Contrary to this viewpoint, others argue
(Page, 1982; Tipler, 1986, 2000; Albert and Loewer, 1988; Albert, 1992;
Vaidman, 1994, 1998, 1999; Price, 1995; Lockwood, 1996; Deutsch, 1996;
Deutsch and Hayden, 2000) that the Everett interpretation can in fact
resolve the apparent contradiction between locality and quantum mechanics.
In particular, Deutsch and Hayden (2000) apply the Everett interpretation
to quantum mechanics in the Heisenberg picture, and show that in EPRB
experiments,1 information regarding the correlations between systems is
encoded in the Heisenberg-picture operators corresponding to the
observables of the systems, and is carried from system to system and from
place to place in a local manner. The picture which emerges is not one of
measurement-type interactions “splitting the universe” but, rather,
producing copies of the observers and observed physical systems which have
interacted during the (local) measurement process (Tipler, 1986).

Two more by Rubin:
http://arxiv.org/abs/quant-ph/0204024
http://arxiv.org/abs/0909.2673

Conceptually it's not that hard to see how the MWI offers a loophole in
Bell's proof--Bell assumed that each spin measurement yielded a single
definite outcome, but if you instead imagine that each spin measurement
causes the experimenter to split into copies who observe different outcomes
and aren't aware of one another, then the universe doesn't have to decide
which version of experimenter #1 gets matched up to which version of
experimenter #2 until there's been time for signals moving at the speed of
light to travel from each experimenter to someone in the middle who can be
aware of the results at both locations. If that isn't clear, in post #11 at
http://www.physicsforums.com/showthread.php?t=206291 I gave a sort of toy
model of how duplicating the experimenters at different locations and
matching them up later can allow for each of the matched pairs to observe
Bell inequality violations without any need for nonlocality.

Jesse




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Re: What are wavefunctions?

2014-01-09 Thread meekerdb

On 1/9/2014 9:45 AM, John Clark wrote:

On Wed, Jan 8, 2014 at 6:59 PM, LizR lizj...@gmail.com 
mailto:lizj...@gmail.com wrote:

 I'm arguing that time is symmetric,


 Good luck winning that argument when nearly everything we observe, 
from
cosmology to cooking, screams at us that time is NOT symmetric.


 Not at the quantum level,


If so then obviously the quantum level is not the end of the story.


 it was actually discovered before Bell died that there's a 
perfectly
reasonable explanation for how his inequality can be violated that 
retains
locality and realism.


 Baloney.


 If that's the best refutation you can come up with, John Bell and Huw 
Price have
nothing to fear.


They have nothing to fear from me or the truth. If retro-causality exists then things 
are not local and not realistic either, so that possibility has not been ruled out 
experimentally.


Retro-causality is always present in a deterministic system because boundary conditions 
can be in the future instead of the past.  Newtonian mechanics included retro-causality 
and was still realistic (in the sense of only one definite result).  MWI is the same, 
deterministic and one definite result - except the definite result includes 
non-communicating worlds including the observers. Maybe it should be called the hidden 
worlds theory.


Brent


But the common sense view that most people, including Einstein, had about reality, that 
things are realistic and local, CAN be ruled out. And of all the people on the planet 
John Bell would be the last to disagree that if his inequality is violated then things 
are not local or not realistic or not either.


 John K Clark





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Re: What are wavefunctions?

2014-01-09 Thread meekerdb

On 1/9/2014 9:58 AM, John Clark wrote:

That and the equations of cosmology.


The equations of cosmology, Einsteins or Wheeler-Dewitt, are T-symmetric.  You seem to 
have confused the equations of evolution and the boundary conditions.


Brent

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Re: What are wavefunctions?

2014-01-09 Thread John Clark
On Thu, Jan 9, 2014 at 2:02 PM, Jesse Mazer laserma...@gmail.com wrote:

 And as I've said, there is also the fact that if the laws of physics
 don't conserve phase space volume, the 2nd law wouldn't hold either.


You've got it backwards, there is no fundamental law of physics concerning
the conservation of phase space that forces matter to behave in certain
ways, rather it's just a natural consequence of the FIRST law of
thermodynamics and the statistical fact that if you make a change in a
highly orders system you will probably make it more disordered because
there are far fewer ordered states than disordered states. Liouville's
equation is all about statistics, the variables in it determine the phase
space distribution and that determines the PROBABILITY a system of things
will be in a particular infinitesimal phase space volume.

 For example, in Life one could define macrostates in terms of the ratio
 of white to black cells [...]


  In the Game of Life the number of black cells is always infinite, so I
 don't see how you can do any ratios.



 Maybe that would be true for some ideal Platonic version of the Game of
 Life on an infinite board, but any real-world implementation of a cellular
 automaton involves a finite number of squares


Maybe not. The universe is certainly a real world implementation and it
might be infinite and it might be a cellular automation, that's what
Stephen Wolfram thinks.

 usually this is done with a periodic boundary condition, so squares on
 the left edge of the finite grid are defined to be neighbors of squares on
 the right edge, and squares on the top edge of the grid are defined to be
 neighbors of squares on the bottom edge.


Then the rules governing the game have been changed.

 Another alternative would be to imagine you do have an infinite grid, but
 with a starting state where there are only a finite pattern of black
 squares surrounded by an infinite number of white squares,


So the ratio of white squares to black is a finite number divided by
infinity. Perhaps that's what a Black Hole is, a place where God tried to
divide by zero.

  John K Clark

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Re: What are wavefunctions?

2014-01-09 Thread Jesse Mazer
On Thu, Jan 9, 2014 at 3:58 PM, John Clark johnkcl...@gmail.com wrote:

 On Thu, Jan 9, 2014 at 2:02 PM, Jesse Mazer laserma...@gmail.com wrote:

  And as I've said, there is also the fact that if the laws of physics
 don't conserve phase space volume, the 2nd law wouldn't hold either.


 You've got it backwards, there is no fundamental law of physics concerning
 the conservation of phase space that forces matter to behave in certain
 ways, rather it's just a natural consequence of the FIRST law of
 thermodynamics and the statistical fact that if you make a change in a
 highly orders system you will probably make it more disordered because
 there are far fewer ordered states than disordered states.


I never claimed Liouville's theorem was a fundamental law of physics in
itself, rather it is derivable as a mathematical consequence of certain
features of the fundamental laws. What I've read indicates that Liouville's
theorem applies to any system that obeys Hamilton's equations (see the last
paragraph on p. 549 of Taylor's Classical Mechanics at
http://books.google.com/books?id=P1kCtNr-pJsCpg=PA549 for example), but
I'm not sure if it's true that any logically possible laws that conserve
energy (obeying the first law of thermodynamics) also obey Hamilton's
equations...the Hamiltonian is not always equal to the total energy, see
http://physics.stackexchange.com/questions/11905/when-is-the-hamiltonian-of-a-system-not-equal-to-its-total-energy




 Liouville's equation is all about statistics, the variables in it
 determine the phase space distribution and that determines the PROBABILITY
 a system of things will be in a particular infinitesimal phase space volume.


Liouville's theorem is derived in deterministic classical mechanics. If you
take a volume of phase space, each point in that volume is a specific
microstate, and if you evolve each microstate forward for some time T using
the deterministic equations of physics, you get a later set of microstates
which occupy their own volume in phase space. Liouville's theorem just says
the two volumes must be equal. It only becomes statistical if you interpret
the original set of microstates as representing your own uncertainty--if
you just know the original macrostate, you may choose to consider the
statistical ensemble of microstates compatible with that macrostate, then
they will give the volume of phase space that you start with. But that's
just an extra layer of interpretation, Liouville's theorem itself is not
really statistical.



  For example, in Life one could define macrostates in terms of the
 ratio of white to black cells [...]


  In the Game of Life the number of black cells is always infinite, so
 I don't see how you can do any ratios.



  Maybe that would be true for some ideal Platonic version of the Game of
 Life on an infinite board, but any real-world implementation of a cellular
 automaton involves a finite number of squares


 Maybe not. The universe is certainly a real world implementation and it
 might be infinite and it might be a cellular automation, that's what
 Stephen Wolfram thinks.



This line of discussion got started because I was disputing your statement
that we can derive the 2nd law in a *purely* logical way like 2+2=5, with
no need to invoke knowledge about the laws of physics that was based on
observation. This would imply that *any* logically possible mathematical
laws of nature would obey the 2nd law. So the question of whether space in
*our* universe is infinite or finite is irrelevant to the discussion,
because it's certainly logically possible to have a universe with finite
space.

If you did not mean to suggest that we can know a priori the 2nd law is
true because it would be true in any logically possible universe whose
behavior follows mathematical laws, please clarify. But I thought you were
talking about logically possible universes as well, not just our
universe--the very fact that you were willing to discuss the Game of Life
suggested this, since even though it's possible our universe could be a
cellular automaton, I think we can be pretty confident it's not a
2-dimensional cellular automaton like the Game of Life!




  usually this is done with a periodic boundary condition, so squares on
 the left edge of the finite grid are defined to be neighbors of squares on
 the right edge, and squares on the top edge of the grid are defined to be
 neighbors of squares on the bottom edge.


 Then the rules governing the game have been changed.


I think most any book or website that defines the rules of the Game of
Life will just state the transition rules for how each cell's state depends
on the state of that cell and its nearest neighbors on the previous
time-step, they don't say anything about whether the topology of the board
is that of a torus (which is topologically equivalent to a square with the
edges identified in the way I described, as discussed at
http://plus.maths.org/content/space-do-all-roads-lead-home ) 

Re: What are wavefunctions?

2014-01-09 Thread LizR
On 10 January 2014 06:58, John Clark johnkcl...@gmail.com wrote:

 On Wed, Jan 8, 2014 at 7:11 PM, LizR lizj...@gmail.com wrote:

  The equations of Newtonian dynamics are time-symmetric,


 I know.

  similarly for relativity both SR and GR -


 I know

  and quantum mechanics is, too.


 I know.

  The only thing in the entirety f physics that isn't based on time
 symmetric equations is thermodynamics,


 That and the equations of cosmology. And astrophysics. And meteorology.
 And [...]


So stop pretending otherwise.

As a lot of people have now pointed out, physics can be local and relistic
if time symmetry is valid.

Time symmetry appears to be valid, as you just agreed.

Hence physics can be local and realistic.

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