Re: Non-locality and MWI

[Brent Meeker]

?? Every time you perceive something visually you've mined data from 
your light cone.


Brent

On 4/18/2016 8:29 PM, spudboy100 via Everything List wrote:
This is a foolish, but related question. It is, is there a means, in 
princple, to somehow data mine the minkowski light cone? Conceptually, 
its photons interacting with baryons of one sort or another, so ought 
now the photon patterns of interactions with the old Bohr model of 
particles?  Its a question that I ponder every once in a while.


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Re: Non-locality and MWI

[Bruce Kellett]

On 19/04/2016 10:23 am, Jesse Mazer wrote:
On Mon, Apr 18, 2016 at 3:45 AM, Bruce Kellett 
> wrote:



The local mathematical rule in this case, say for observer A, is
that measurement on his own local particle with give either |+> or
|->, with equal probability. It does not matter how many copies
you generate, the statistics remain the same. I am not sure
whether your multiple copies refer to independent repeats of the
experiment, or simply multiple copies of the observer with the
result he actually obtained. The set of outcomes on the past light
cone for this observer is irrelevant for the single measurement
that we are considering. Taking such copies can be local, but the
utility remains to be demonstrated.



Sorry if I was unclear, I thought we were on the same page about the 
notion of "copies". The copies in my toy model are supposed to 
represent the idea in the many-worlds that there are multiple 
equally-real versions of a single system at a single location at a 
single time, including human experimenters, and that in any quantum 
experiment some versions will record one result and others will record 
a different one. So the copies represent different parallel versions 
of a simulated observer, and just as in the MWI, some copies see one 
result and other copies see a different result for any *single* 
experiment (and each copy retains a memory, so different copies 
remember different sequences of past results as well). And as in the 
MWI, these copies would be unaware of one another--just imagine 
several simulations of the same experimenter at the same time running 
in parallel, with different variations on what results the simulation 
feeds to them.


I have a couple of questions. Firstly, does the ensemble generated in 
this way differ in any significant respect from the one generated if the 
same Alice and Bob perform their (random orientation) measurements a 
large number of times? And secondly, what exactly are they performing 
their measurements on? On random unpolarized particles? or always on one 
of the particles of an entangled singleton pair? In the latter case, one 
would assume that we have to keep track of which Alice result comes from 
the same pair as which Bob result. In other words, the ensemble is 
identical to the one generated by many runs of the same experiment, on 
entangled pairs, by the same observes.


A common topic of discussion on everything-list is the subject of 
"first-person indeterminacy", which would be expected to result when 
the pattern of a given physical brain is duplicated (I haven't been 
following a lot of recent threads so I don't know if you've already 
weighed in on this topic before). You could imagine an actual 
atom-for-atom duplicate of a biological person, but to avoid 
objections based on the uncertainty principle and no-cloning theorem, 
let's instead suppose the person in question is that of a "mind 
upload"--a very realistic simulation of a human brain (at the level of 
synapses or lower) running on a computer, which most on this list 
would assume would be just as conscious as a biological brain. If the 
computer is a deterministic classical one, then if the simulated brain 
is in a simulated body in a simulated environment which is closed off 
from outside input and that also evolves deterministically, then if a 
copy is made of the program with the same starting conditions and the 
copies run in parallel on two different computers, the behavior (and 
presumably inner experiences) of the upload should be the same. But 
say that after the two programs have been running in parallel for a 
while there is a plan to produce a difference, with a screen inside 
the simulation flashing blue in one simulation, yellow in the other 
simulation. When that happens, the behavior and experiences of the two 
copies of the uploaded brain should diverge somewhat (and probably 
continue to diverge even more over time, since sensitive dependence on 
initial conditions--the 'butterfly effect'--very likely applies to 
brain dynamics). If the upload knows in advance that the experiment 
will work this way, then before the screen flashes a color, it would 
make sense for him to reason as if it's a probabilistic event, with a 
50% chance of the screen showing blue and a 50% chance of it showing 
yellow. On the other hand, if he knows that 9 copies of the program 
will be shown slightly different (but distinguishable) shades of blue 
but only one will be shown a yellow screen, it makes sense for him to 
reason as if there is a 9:1 probability he will see a blue screen, 
given that after the experiment is complete there will be 9 variants 
of him that remember a blue screen and only 1 that remembers a yellow 
screen. If he has to bet something of value to him on the outcome, he 
will assume 50/50 odds of seeing blue in the first type of experiment 
and 90/10 odds 

Re: Non-locality and MWI

[spudboy100 via Everything List]

This is a foolish, but related question. It is, is there a means, in princple, 
to somehow data mine the minkowski light cone? Conceptually, its photons 
interacting with baryons of one sort or another, so ought now the photon 
patterns of interactions with the old Bohr model of particles?  Its a question 
that I ponder every once in a while.

Sent from AOL Mobile Mail


-Original Message-
From: Jesse Mazer 
To: everything-list 
Sent: Mon, Apr 18, 2016 08:23 PM
Subject: Re: Non-locality and MWI






On Mon, Apr 18, 2016 at 3:45 AM, Bruce Kellett 
bhkell...@optusnet.com.au> 
wrote:

  

  
  

On 18/04/2016 5:00 pm, Jesse Mazer wrote:


  On Mon, Apr 18, 2016 at 1:37 AM, Bruce Kellett bhkell...@optusnet.com.au>
wrote:


  

   On
  18/04/2016 2:53 pm, Jesse Mazer wrote:

  
On Sun, Apr 17, 2016 at 9:19 PM,
  Bruce Kellett mailto:bhkell...@optusnet.com.au;>bhkell...@optusnet.com.au> 
wrote:

  

  On
  18/04/2016 10:11 am, Jesse Mazer wrote:

  

  
On Sun, Apr
  17, 2016 at 7:34 PM, Bruce
  Kellett mailto:bhkell...@optusnet.com.au;>bhkell...@optusnet.com.au> 
wrote:

  

The future light cones of the
observers will overlap at a time
determined by their initial
separation, regardless of
whether they send signals to
each other or not.

  
  

  
  
Of course, I never meant to
suggest otherwise. Imagining a
central observer who receives
messages about each experiment
was just conceptually simpler
than imagining an arbitrary
system that is affected in some
unspecified way by each
experimenter's results along
with every other part of that
system's past light cone. But
you certainly don't *need* to
use that particular example.

  

  
  

The issue is to find a local
explanation of the correlations: appealing
to some arbitrary system that is affected in
some unspecified way. But my example shows
that no exchange of information after the
separate worlds of the two experimenters
have fully decohered can ever explain the
quantum correlations.






Why do you think it shows that? Does
  "explain" mean something more than giving a
  mathematical model that generates the correct
  correlations, or is that sufficient?
  

  
  

 Have you not understood my argument? The
specified experiment results in four possible
combinations of results: |+>|+'>, |+>|-'>,
|->|+'>, and |->|-'>. It is relatively easy
to show, either by looking at special cases, or by
consideration of a repeated sequence of such
experiments, that the probabilities are different for
each of the four sets of results. The differences in
probability depend only on the relative orientations of
the measuring magnets. Conveying this angle information
after the experiment 

Re: Non-locality and MWI

[Jesse Mazer]

On Mon, Apr 18, 2016 at 3:45 AM, Bruce Kellett 
wrote:

> On 18/04/2016 5:00 pm, Jesse Mazer wrote:
>
> On Mon, Apr 18, 2016 at 1:37 AM, Bruce Kellett 
> wrote:
>
>> On 18/04/2016 2:53 pm, Jesse Mazer wrote:
>>
>> On Sun, Apr 17, 2016 at 9:19 PM, Bruce Kellett <
>> bhkell...@optusnet.com.au> wrote:
>>
>>> On 18/04/2016 10:11 am, Jesse Mazer wrote:
>>>
>>> On Sun, Apr 17, 2016 at 7:34 PM, Bruce Kellett <
>>> bhkell...@optusnet.com.au> wrote:
>>>

 The future light cones of the observers will overlap at a time
 determined by their initial separation, regardless of whether they send
 signals to each other or not.

>>>
>>> Of course, I never meant to suggest otherwise. Imagining a central
>>> observer who receives messages about each experiment was just conceptually
>>> simpler than imagining an arbitrary system that is affected in some
>>> unspecified way by each experimenter's results along with every other part
>>> of that system's past light cone. But you certainly don't *need* to use
>>> that particular example.
>>>
>>>
>>> The issue is to find a local explanation of the correlations: appealing
>>> to some arbitrary system that is affected in some unspecified way. But my
>>> example shows that no exchange of information after the separate worlds of
>>> the two experimenters have fully decohered can ever explain the quantum
>>> correlations.
>>>
>>
>> Why do you think it shows that? Does "explain" mean something more than
>> giving a mathematical model that generates the correct correlations, or is
>> that sufficient?
>>
>>
>> Have you not understood my argument? The specified experiment results in
>> four possible combinations of results: |+>|+'>, |+>|-'>, |->|+'>, and
>> |->|-'>. It is relatively easy to show, either by looking at special cases,
>> or by consideration of a repeated sequence of such experiments, that the
>> probabilities are different for each of the four sets of results. The
>> differences in probability depend only on the relative orientations of the
>> measuring magnets. Conveying this angle information after the experiment
>> has been completed, and each of the measurements has totally decohered,
>> cannot explain these correlations.
>>
>> What is required is an account of how these correlations can arise
>> *before* A and B speak to each other, because once they have their
>> results in hand, it may be weeks before they actually communicate. Rubin's
>> argument (following from Deutsch) does not achieve this.
>>
>
>
> But as I said, you can achieve it if there is no fact of the matter about
> *both* results except in the overlap region of the future light cone of
> both measurements, where a single localized system may be causally
> influenced by both measurements (see below for more on what I mean by this
> if you're unclear).
>
>
>
>>
>>
>> This so-called "matching up" is pure fantasy. Who does this matching? If
 the central umpire is to do the matching, he has to have the power to
 eliminate cases that disagree with the quantum prediction. Who has that
 power?

>>>
>>>
>>> The laws of physics would do the matching in some well-defined
>>> mathematical way.
>>>
>>>
>>> I agree that the laws of physics will 'prevent' the formation of any
>>> worlds in which the laws of physics are violated. That is not the issue.
>>> The issue is: how do the laws of physics act in order to achieve this. Do
>>> they act locally or non-locally? If they act locally, then you are required
>>> to provided the local mechanism whereby they so act. You are not doing this
>>> at the moment.
>>>
>>
>> Similar to my question above, what do you mean by "mechanism" ? Do you
>> mean something more than simply "mathematical rule that gives you the set
>> of possible outcomes (with associated probabilities or at least probability
>> amplitudes) at each local region of spacetime, given only the set of
>> possible outcomes at regions in the past light cone"?
>>
>>
>> The mathematical rule that gives the differing probabilities for each
>> outcome depending on the relative angle of the magnets is just quantum
>> mechanics. But that is intrinsically non-local
>>
>
> I specified that I was talking about a local mathematical rule--I said the
> rule would give out the outcomes at one location in spacetime "given only
> the set of possible outcomes at regions in the past light cone". Did you
> miss that part, or do you disagree that if I mathematically determine the
> state of some region of spacetime using *only* information about the states
> of regions in the past light cone, that is by definition a local theory?
>
>
> The local mathematical rule in this case, say for observer A, is that
> measurement on his own local particle with give either |+> or |->, with
> equal probability. It does not matter how many copies you generate, the
> statistics remain the same. I am not sure 

Re: Non-locality and MWI

[Bruce Kellett]

On 19/04/2016 12:17 am, Bruno Marchal wrote:

On 18 Apr 2016, at 09:45, Bruce Kellett wrote:


Let me reduce this to simple steps:

1) MWI is an interpretation of QM only. I.e., it reproduces all the 
results of QM without adding any additional structure or dynamics.


What do you mean by QM? I am not sure I agree with you. Everett did 
not talk about a new intepretation of QM, but about a new formulation 
of QM. And he is right in the sense of the logician. Before Everett: 
QM was formulated roughly SWE + Collapse + an implicit dualist theory 
of mind or of scale (mircro/macro). Everett's QM is SWE, the abandon 
of collapse, + a mechanist theory of mind, with the implicit use of 
the FPI.


No, you are confusing the mathematical theory of QM with its various 
interpretations. The mathematical theory of quantum mechanics is the 
theory that associates physical states with vectors in Hilbert space; 
observables with Hermitian operators in that space; and measurement 
results with the eigenvalues of the corresponding operator. Supplemented 
with the Born rule, which states that the probability for obtaining any 
particular eigenvalue as the result of a measurement is given by the 
absolute square of the coefficient of that eigenvalue in the 
superposition describing the state, we get the standard mathematical 
theory of quantum mechanics.


Note that this says nothing about collapse or not, about one or many 
worlds, or about any interpretational issues. Interpretational issues 
are overlaid on this basic theory of QM, and it is central to the whole 
discussion that the predicted experimental results depend only on the 
underlying theory and not on the interpretational superstructure. All 
interpretations must give the same predictions for experimental results 
or else they are alternative theories and not interpretations of 
(standard) QM.


For a logician, if QM (without collapse) is formalized, you get an 
"Herbrand minimal model" which contains already all relative state 
(like we get them already in the sigma_1 arithmetic with the Mechanist 
Hypothesis in the Cognitive Science).


Given the linearity of the tensor product and the evolution, we can 
only abstract away the self-superposition, although we would have to 
take them into account if we get a quantum brain (and here the SWE 
give non ambigous result where a collapse theory has to first make 
more precise how the (non local) collapse is made physically.


I don't know what you are talking about. But you are still confusing the 
theory with its interpretation.


2) The QM state describing an entangled singlet pair does not refer 
to, or depend on, the separation between the particles.


OK. But the singlet state describe an infinity of Bob and Alice with 
their spin correlated, yet both of them see their own particles with a 
random result, as none of them know in which universe they are. They 
know only one thing for sure: their spin are correlated, and remains 
so independently of the distance.


The only thing either of them knows for sure locally is that they have 
50% probability of getting |+> and 50% probability of getting |->. After 
the experiment is complete and completely decohered locally, they have 
just one result. You might interpret this situation by claiming that 
there are two local copies of each, one with |+> and one with |->, but 
that is an interpretation, it is not the mathematical theory, which 
predicts only the probabilities.


3) The quantum calculation of the joint probabilities depends on the 
relative orientation between the separate measurements on the 
separated particles.


No problem.

4) This quantum calculation is the same for any physical separation, 
since the singlet state itself does not depend on the separation.


No problem.

5) The quantum calculation is, therefore, intrinsically non-local 
because it does not depend on the separation, which can be 
arbitrarily large.


This does not follow. It would be if the state |psi> = (|+>|-> - 
|->|+>) would be interpreted by We know that Alice has a particle in 
state |+> or in state |-> and Bob the opposite. But the state (|+>|-> 
- |->|+>)  means eaxctly that neither Alice nor Bob know in which 
universe they are. It could be one with  |+'>  or  |-'> or whatever.


Again, you are confused by the basis issue. The singlet state can be 
expanded in the above form in any basis whatsoever, sure, but you are 
forgetting the crucial matter of contextuality. For Alice, sitting there 
with her EPR particle, the basis in which the singlet state is expanded 
is completely irrelevant -- there is only one Alice at this stage. Once 
she chooses the setting for her magnet, she needs to be able to 
calculate the probabilities for the possible results that she can get. 
To calculate these probabilities she chooses the basis that corresponds 
to the orientation of her magnet. This is the effect of contextuality. 
She could, of course, choose to make her calculations in any of 

Re: Non-locality and MWI

[spudboy100 via Everything List]

Another anology, King Canute of Britian ordering the tides not to come in. 


I am  creepy guy who loves science, not just for the intellectual thrill, but, 
especially, what the hell good can it do us?? I always hold to that, unless the 
topic is so thrilling to me, that I get obsessed. Sometims, Boltzmann Brains do 
this for me, and other times its talking about unicorns and pixies to me. This 
is a narrow minded view, but we have to come out of our ivory tower sometime 
(ivory tower = humn skull). No trade of goods or services with multiple worlds, 
Might as well tell tall tales to the young'ins (Batman-Superman or The Force 
Awakens). 


-Original Message-
From: John Clark 
To: everything-list 
Sent: Mon, Apr 18, 2016 12:47 pm
Subject: Re: Non-locality and MWI



On Sun, Apr 17, 2016 at 10:42 PM, spudboy100 via Everything List 
 wrote:




​> ​
Unless there is some physical ionteraction tween local closely related 
universes, its all bupkas, or cyhers, Its a breath taking concept in the hug 
everett sense of things, but we might as well be discussing harry potter or 
batman worlds.



​
Then I guess we live in a Batman Harry Potter world because things are 
non-local (or worse non-realistic ).
​ ​
It reminds me of the
​ ​
Persian Emperor
​ ​
Xerxes
​ ​
who
​ ​
ordered his men to flog the sea because he
​ ​
commanded
​ ​
the tide not to come
​ ​
​
in
​ ​
but it came in anyway. 
​ ​
And
​ ​
the flogging didn't help, the ocean disobeyed
​ ​
again and came in 12 hours later.


The universe doesn't care if human beings like it or not, if experimental 
results say that's the way things are then that's
​ ​
the way things are. Live with it.
​ ​
As Richard Feynman said:


​"​
Do not keep saying to yourself, if you can possibly
​
 avoid it, "But how can it be like that?" because you will 
​go​
​
 'down the drain', into a blind alley from which nobody has escaped. Nobody 
knows how it can be like that.
​"​




 John K Clark







 











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Re: Counterfactual Definiteness

[John Mikes]

Bruno et al:
I think *"definiteness"* is always counterfactual since it *MUST* deny the
potential influences from unknown factors (domains, a/effects, even some
definitely counterfactual influences we do not recognize as such at all).
It is a consequence of our agnostic view (as I recall: we agreed on such,
 at least to some degree) and our (accepted?) view on 'scientific' - as
doubtful.
I mean the 'counterfactual' mildly: it "counters" the factual *TOTAL*
impact, not necessarily negating all the infuences. Our views are partial
at best.

I do not know much about rhe QM-related readings and am too old already to
start learning. I accept my ignorance and try to live with it as long as I
can.

John Mikes

On Sun, Apr 17, 2016 at 1:42 PM, Bruno Marchal  wrote:

>
> On 16 Apr 2016, at 01:46, Bruce Kellett wrote:
>
> On 16/04/2016 12:20 am, Bruno Marchal wrote:
>
> On 14 Apr 2016, at 14:31, Bruce Kellett wrote:
>
> It is interesting that you have not answered my question about what
> exactly you mean by 'counterfactual definiteness' so that we know what you
> mean when you say that a theory is not counterfactually definite.
>
>
> It is hard to define, especially if we avoid being technical. But we have
> a good example: QM-with-collapse (or QM with a single universe). Like
> Einstein already explain at the Solvay Meeting: if QM (with a single
> universe) is correct, we can't ascribe an element of reality knowing a
> result that we would obtain with certainty if we would make some
> measurement, but will not do. Then Kochen and Specker proved that QM (+ a
> single universe) is precisely like that. The proof does not apply to the
> many-world, although it might apply to some too much naive rendering of the
> many world (notably if we interpret wrongly the singlet state as I have
> explained in previous post).
>
>
> I do not understand what you are saying. Are you claiming that ordinary QM
> with collapse is counterfactually definite because Einstein realism does
> not apply?
>
>
>
>
>
> I say the contrary: t is NOT counterfactual making Einstein realism not
> able to be applied.
>
>
>
>
>
>
>
> I.e., we cannot know with certainty what would have been the outcome of an
> experiment that was not performed? (This is also the consequence of the
> Kochen-Specker result that no set of hidden variables can predict the
> results of all possible spin measurements on a spin 1/2 particle.) I would
> have thought that this was one possible definition of counterfactual
> *indefiniteness*.
>
>
> I would be OK too.
>
>
>
>
> What additional fact about MWI changes this conclusion?
>
>
> None. Except that with a single physical reality that counterfactualness
> entails non locality, but the same conunterfactualness with eother
> computationalism and/or QM-without collapse does not entail physical nopn
> locality, but only its statistical *appearances* in the memory of the
> machine testing it.
>
>
>
>
> Since in MWI all possible experiments are performed in some word or other,
> I would have thought that experimental outcomes are available for all
> possible experiments -- nothing is *actually* indefinite
>
>
> It is relatively to you knowledge of a state. If you measure the position
> very precisely, you "soul" is attached to an infinity of
> "body/representation" with many definite, but different, momenta.
>
> If you measure something the result is definite only relatively to one
> representation among many. If you look at the transfer of information in
> the 3p picture of the entire quantum teleportation, you can see that the
> information is spread locally at all times. It is even somehow made
> explicit if you are using Bob Coecke's use category to describe such
> quantum events.
>
> http://arxiv.org/abs/quant-ph/0402130
> http://arxiv.org/abs/quant-ph/0402014
>
> -- even though not all outcomes occur in this one world that we happen to
> inhabit at the moment.
>
>
> There is no real sense to say that we inhabit a world. We are all the
> times in an infinity of worlds/situation, which differentiate or not
> relatively to what we interact with.
> An electronic orbital is a sort of map of the set of all words we are
> relatively to the possible energy of that "electron".
> But by the linearity of the tensor product, we share the worlds only with
> the person we interact with.
> You might look at the Rubin's paper (provided by Scerir). Or Bob's Coocke.
>
> I will comment your other post with more detail perhaps later. But I do
> not really grasp your
>
> <<
> A and B perform their measurements at spacelike separation, but each
> chooses the measurement orientation outside the light cone of the other.
> There are four possible combinations of results, corresponding to four
> worlds in the
> MWI: |+>|+'>, |+>|-'>, |->|+'>, and |->|-'>.
> Since each observer has a 50% chance of getting |+> and 50% of getting
> |->, and the two measurements are completely independent of each other, it
> would seem that each of 

Re: Non-locality and MWI

[John Clark]

On Sun, Apr 17, 2016  Bruce Kellett  wrote:

​
>> ​>> ​
>> So is there a way of knowing which of the 4 yous is you other than by
>> observing what Alice and Bob are observing? I
>> ​
>> f there is I can't imagine what it could be.
>
>
> ​> ​
> There doesn't need to be.
>

​If you want to know what the results of the experiment are you're going to
have to know which of the 4 yous is you. ​



> ​> ​
> I worry only about the Alice and Bob with whom I share a cup of coffee
> while they discuss their results.
>

​That specification is not​

​good enough because all 4 yous share a cup of coffee with Alice and Bob,
but only one of the 4 yous can truthfully say "I see my electron as spin
down and your electron as ​spin up", so if you say that then that you must
be you.

 John K Clark







>
>
> ​ >
 ​ >>​
 ​You appear to have a clear grasp of the situation -- either QM is
 intrinsically non-local, or we have magic..
>>>
>>>
>>> ​ >> ​
>>> Or
>>> ​
>>>  non-realism.
>>
>> ​ > ​
>> If by non-realism you mean some version of Einstein's "elements of
>> reality",
>>
>
> ​Einstein believed in realism even more than he believed in determinism
> or locality, that's why he said the moon existed even when nobody was
> looking at it.
>
>  John K Clark
>
>
> --
> You received this message because you are subscribed to the Google Groups
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Re: Non-locality and MWI

[Bruno Marchal]

On 18 Apr 2016, at 09:45, Bruce Kellett wrote:


On 18/04/2016 5:00 pm, Jesse Mazer wrote:
On Mon, Apr 18, 2016 at 1:37 AM, Bruce Kellett  wrote:

On 18/04/2016 2:53 pm, Jesse Mazer wrote:
On Sun, Apr 17, 2016 at 9:19 PM, Bruce Kellett  wrote:

On 18/04/2016 10:11 am, Jesse Mazer wrote:
On Sun, Apr 17, 2016 at 7:34 PM, Bruce Kellett  wrote:


The future light cones of the observers will overlap at a time  
determined by their initial separation, regardless of whether  
they send signals to each other or not.


Of course, I never meant to suggest otherwise. Imagining a  
central observer who receives messages about each experiment was  
just conceptually simpler than imagining an arbitrary system that  
is affected in some unspecified way by each experimenter's  
results along with every other part of that system's past light  
cone. Butyou certainly  
don't *need* to use that particular example.


The issue is to find a local explanation of the correlations:  
appealing to some arbitrary system that is affected in some  
unspecified way. But my example shows that no exchange of  
information after the separate worlds of the two experimenters  
have fully decohered can ever explain the quantum correlations.


Why do you think it shows that? Does "explain" mean something more  
than giving a mathematical model that generates the correct  
correlations, or is that sufficient?


Have you not understood my argument? The specified experiment  
results in four possible combinations of results: |+>|+'>, |+>|-'>,  
|->|+'>, and |->|-'>. It is relatively easy to show, either by  
looking at special cases, or by consideration of a repeated  
sequence of such experiments, that the probabilities are different  
for each of the four sets of results. The differences in  
probability depend only on the relative orientations of the  
measuring magnets. Conveying this angle information after the  
experiment has been completed, and each of the measurements has  
totally decohered, cannot explain these correlations.


What is required is an account of how these correlations can arise  
before A and B speak to each other, because once they have their  
results in hand, it may be weeks before they actually communicate.  
Rubin's argument (following from Deutsch) does not achieve this.



But as I said, you can achieve it if there is no fact of the matter  
about *both* results except in the overlap region of the future  
light cone of both measurements, where a single localized system  
may be causally influenced by both measurements (see below for more  
on what I mean by this if you're unclear).





This so-called "matching up" is pure fantasy. Who does this  
matching? If the central umpire is to do the matching, he has to  
have the power to eliminate cases that disagree with the quantum  
prediction. Who has that power?



The laws of physics would do the matching in some well-defined  
mathematical way.


I agree that the laws of physics will 'prevent' the formation of  
any worlds in which the laws of physics are violated. That is not  
the issue. The issue is: how do the laws of physics act in order  
to achieve this. Do they act locally or non-locally? If they act  
locally, then you are required to provided the local mechanism  
whereby they so act. You are not doing this at the moment.


Similar to my question above, what do you mean by "mechanism" ? Do  
you mean something more than simply "mathematical rule that gives  
you the set of possible outcomes (with associated probabilities or  
at least probability amplitudes) at each local region of  
spacetime, given only the set of possible outcomes at regions in  
the past light cone"?


The mathematical rule that gives the differing probabilities for  
each outcome depending on the relative angle of the magnets is just  
quantum mechanics. But that is intrinsically non-local


I specified that I was talking about a local mathematical rule--I  
said the rule would give out the  outcomes at one  
location in spacetime "given only the set of possible outcomes at  
regions in the past light cone". Did you miss that part, or do you  
disagree that if I mathematically determine the state of some  
region of spacetime using *only* information about the states of  
regions in the past light cone, that is by definition a local theory?


The local mathematical rule in this case, say for observer A, is  
that measurement on his own local particle with give either |+> or |- 
>, with equal probability. It does not matter how many copies you  
generate, the statistics remain the same. I am not sure whether your  
multiple copies refer to independent repeats of the experiment, or  
simply multiple copies of the observer with the result he actually  
obtained. The set of outcomes on the past light cone for this  
observer is irrelevant for 

R: Re: Non-locality and MWI

['scerir' via Everything List]

Jesse wrote:I don't think this is how it's supposed to work for those who argue 
the MWI is local like Deutsch. Rather the idea is that "splitting" into worlds 
is local, not global; so one experimenter locally splits into copies that see 
|+> and |-> when they measure their particle, likewise the other experimenter 
splits into copies that saw |+'> and |-'>. But until their future light cones 
overlap there are no "worlds" containing facts about what *both* experimenters 
saw.
-
In a Franson interferometer, two (time-energy entangled photons) travel in 
opposite directions from an EPR source. Each photon then enters an *imbalanced* 
Mach-Zehnder interferometer (such that there is
no single-photon interference in each Mach-Zehnder interferometer). 
Detectors measure the outputs of the two identical imbalanced Mach-Zehnder 
interferometers and the
coincidences between the detectors are recorded, showing there is a *two-photon*
interference, that is to say the two entangled potons follow the *same* path
in each (space-like separated) interferometer. A sign of non-locality 
(non-separability) in the "usual"
interpretation. 
I'm trying to figure out how all that works in a *local* MWI ..



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Re: Non-locality and MWI

[Bruce Kellett]

On 18/04/2016 5:00 pm, Jesse Mazer wrote:
On Mon, Apr 18, 2016 at 1:37 AM, Bruce Kellett 
> wrote:


On 18/04/2016 2:53 pm, Jesse Mazer wrote:

On Sun, Apr 17, 2016 at 9:19 PM, Bruce Kellett
> wrote:

On 18/04/2016 10:11 am, Jesse Mazer wrote:

On Sun, Apr 17, 2016 at 7:34 PM, Bruce Kellett
> wrote:


The future light cones of the observers will overlap at
a time determined by their initial separation,
regardless of whether they send signals to each other or
not.


Of course, I never meant to suggest otherwise. Imagining a
central observer who receives messages about each experiment
was just conceptually simpler than imagining an arbitrary
system that is affected in some unspecified way by each
experimenter's results along with every other part of that
system's past light cone. But you certainly don't *need* to
use that particular example.


The issue is to find a local explanation of the correlations:
appealing to some arbitrary system that is affected in some
unspecified way. But my example shows that no exchange of
information after the separate worlds of the two
experimenters have fully decohered can ever explain the
quantum correlations.


Why do you think it shows that? Does "explain" mean something
more than giving a mathematical model that generates the correct
correlations, or is that sufficient?


Have you not understood my argument? The specified experiment
results in four possible combinations of results: |+>|+'>,
|+>|-'>, |->|+'>, and |->|-'>. It is relatively easy to show,
either by looking at special cases, or by consideration of a
repeated sequence of such experiments, that the probabilities are
different for each of the four sets of results. The differences in
probability depend only on the relative orientations of the
measuring magnets. Conveying this angle information after the
experiment has been completed, and each of the measurements has
totally decohered, cannot explain these correlations.

What is required is an account of how these correlations can arise
/before/ A and B speak to each other, because once they have their
results in hand, it may be weeks before they actually communicate.
Rubin's argument (following from Deutsch) does not achieve this.



But as I said, you can achieve it if there is no fact of the matter 
about *both* results except in the overlap region of the future light 
cone of both measurements, where a single localized system may be 
causally influenced by both measurements (see below for more on what I 
mean by this if you're unclear).





This so-called "matching up" is pure fantasy. Who does
this matching? If the central umpire is to do the
matching, he has to have the power to eliminate cases
that disagree with the quantum prediction. Who has that
power?



The laws of physics would do the matching in some
well-defined mathematical way.


I agree that the laws of physics will 'prevent' the formation
of any worlds in which the laws of physics are violated. That
is not the issue. The issue is: how do the laws of physics
act in order to achieve this. Do they act locally or
non-locally? If they act locally, then you are required to
provided the local mechanism whereby they so act. You are not
doing this at the moment.


Similar to my question above, what do you mean by "mechanism" ?
Do you mean something more than simply "mathematical rule that
gives you the set of possible outcomes (with associated
probabilities or at least probability amplitudes) at each local
region of spacetime, given only the set of possible outcomes at
regions in the past light cone"?


The mathematical rule that gives the differing probabilities for
each outcome depending on the relative angle of the magnets is
just quantum mechanics. But that is intrinsically non-local


I specified that I was talking about a local mathematical rule--I said 
the rule would give out the outcomes at one location in spacetime 
"given only the set of possible outcomes at regions in the past light 
cone". Did you miss that part, or do you disagree that if I 
mathematically determine the state of some region of spacetime using 
*only* information about the states of regions in the past light cone, 
that is by definition a local theory?


The local mathematical rule in this case, say for observer A, is that 
measurement on his own local particle with give either |+> or |->, with 
equal probability. It 

Re: Non-locality and MWI

[Jesse Mazer]

On Mon, Apr 18, 2016 at 1:37 AM, Bruce Kellett 
wrote:

> On 18/04/2016 2:53 pm, Jesse Mazer wrote:
>
> On Sun, Apr 17, 2016 at 9:19 PM, Bruce Kellett 
>  wrote:
>
>> On 18/04/2016 10:11 am, Jesse Mazer wrote:
>>
>> On Sun, Apr 17, 2016 at 7:34 PM, Bruce Kellett <
>> bhkell...@optusnet.com.au> wrote:
>>
>>>
>>> The future light cones of the observers will overlap at a time
>>> determined by their initial separation, regardless of whether they send
>>> signals to each other or not.
>>>
>>
>> Of course, I never meant to suggest otherwise. Imagining a central
>> observer who receives messages about each experiment was just conceptually
>> simpler than imagining an arbitrary system that is affected in some
>> unspecified way by each experimenter's results along with every other part
>> of that system's past light cone. But you certainly don't *need* to use
>> that particular example.
>>
>>
>> The issue is to find a local explanation of the correlations: appealing
>> to some arbitrary system that is affected in some unspecified way. But my
>> example shows that no exchange of information after the separate worlds of
>> the two experimenters have fully decohered can ever explain the quantum
>> correlations.
>>
>
> Why do you think it shows that? Does "explain" mean something more than
> giving a mathematical model that generates the correct correlations, or is
> that sufficient?
>
>
> Have you not understood my argument? The specified experiment results in
> four possible combinations of results: |+>|+'>, |+>|-'>, |->|+'>, and
> |->|-'>. It is relatively easy to show, either by looking at special cases,
> or by consideration of a repeated sequence of such experiments, that the
> probabilities are different for each of the four sets of results. The
> differences in probability depend only on the relative orientations of the
> measuring magnets. Conveying this angle information after the experiment
> has been completed, and each of the measurements has totally decohered,
> cannot explain these correlations.
>
> What is required is an account of how these correlations can arise
> *before* A and B speak to each other, because once they have their
> results in hand, it may be weeks before they actually communicate. Rubin's
> argument (following from Deutsch) does not achieve this.
>


But as I said, you can achieve it if there is no fact of the matter about
*both* results except in the overlap region of the future light cone of
both measurements, where a single localized system may be causally
influenced by both measurements (see below for more on what I mean by this
if you're unclear).



>
>
> This so-called "matching up" is pure fantasy. Who does this matching? If
>>> the central umpire is to do the matching, he has to have the power to
>>> eliminate cases that disagree with the quantum prediction. Who has that
>>> power?
>>>
>>
>>
>> The laws of physics would do the matching in some well-defined
>> mathematical way.
>>
>>
>> I agree that the laws of physics will 'prevent' the formation of any
>> worlds in which the laws of physics are violated. That is not the issue.
>> The issue is: how do the laws of physics act in order to achieve this. Do
>> they act locally or non-locally? If they act locally, then you are required
>> to provided the local mechanism whereby they so act. You are not doing this
>> at the moment.
>>
>
> Similar to my question above, what do you mean by "mechanism" ? Do you
> mean something more than simply "mathematical rule that gives you the set
> of possible outcomes (with associated probabilities or at least probability
> amplitudes) at each local region of spacetime, given only the set of
> possible outcomes at regions in the past light cone"?
>
>
> The mathematical rule that gives the differing probabilities for each
> outcome depending on the relative angle of the magnets is just quantum
> mechanics. But that is intrinsically non-local
>

I specified that I was talking about a local mathematical rule--I said the
rule would give out the outcomes at one location in spacetime "given only
the set of possible outcomes at regions in the past light cone". Did you
miss that part, or do you disagree that if I mathematically determine the
state of some region of spacetime using *only* information about the states
of regions in the past light cone, that is by definition a local theory?


>
> You are claiming to have a local account. But I have not yet seen it.
> Published attempts fail for the reasons given.
>

Can you actually follow the detailed math of Rubin's argument in a
step-by-step way, and identify the first step that's an error? Or are you
just saying that your conceptual argument is sufficient to show that any
such attempt is impossible, regardless of the details? If you're making an
impossible-in-principle argument, I think a simple toy model like the one I
described is sufficient to show your argument