Re: Non-locality and MWI

[Brent Meeker]

On 4/19/2016 10:21 PM, smitra wrote:

On 20-04-2016 03:02, Bruce Kellett wrote:

On 20/04/2016 6:56 am, smitra wrote:
The mistake made is to invoke classical reasoning after the 
measurements are made. If the choice for the orientation of the 
polarizers were not made in advance, then Alice and Bob cannot have 
said to have made any definite choices at all.


I think you need to learn something about decoherence , and the
emergence of the 'classical' from the 'quantum'. In the final
analysis, Alice and Bob meet to compare their results. By that stage,
their results, and their relative magnet orientations, are definite
and classical (FAPP if you wish). And that is the end result we have
to explain. All else is boondoggle.


Invoking FAPP is precisely where your argument goes wrong. While due 
to decoherence the macroscopic world looks classical, in reality 
(assuming MWI)  it not classical. This means that when Bob meets with 
Alice that the settings Alice chose are still not determined. It is 
only when Alice communicates to Bob what her polarizer settings were 
that Bob becomes localized in that particular sector of the multiverse 
where this is now fixed.


What if Bob misunderstands what Alice said - does he get localized in a 
different universe.  Does he switch back when Alice shows him her 
notebook?  What if Alice and Bob don't talk directly but instead each 
whispers in Bruce's ear, but they speak urdu so Bruce doesn't know what 
they said until he consults a translator?




If Bob were to be imagined being located in that particular branch 
were Alice had made definite choices and had made definite 
observations, then that implies the existence of an observable for Bob 
that only acts on himself that will yield the exact details of what 
Alice has done. So, Bob could in principle have psychic powers, the 
information of what Alice did would already be present in his brain 
before Alice communicates these to him!


Or, per decoherence, the information was already spread throughout the 
environment (c.f. buckyball experiment) and the environments with 
results for which the Born probability is zero are unobservable.


Brent



Obviously, Bob's brain does not have any information about what Alice 
did until the details are communicated to him. So, Bob's mind is 
identical across the many branches where Alice and, due to 
decoherence, the local environment is different. So, in the experiment 
the effectively classical communication is not at all trivial, in the 
MWI it is a crucial step localizing the observers in the multiverse as 
where the measurements of the spins.


Saibal







Bruce

In some particular sector where Alice made some particular result 
and found some particular result, she knows that Bob's spin state. 
But Bob lives in larger sector of the multiverse which includes 
sectors where Alic had made different choices.


 Alice and Bob communicating later is not some trivial exchange of 
information that existed a priori, it leads to a further de-facto 
collapse of the wavefunction.


There isn't anything more to this that Alice measuring the spin of 
an electron in a lab, and then letting Bob who doesn't know what 
direction the spin was measured in, doing another measurement.


Saibal




--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Cryonics punched cards and the brain

[Bruno Marchal]

On 20 Apr 2016, at 00:12, John Clark wrote:

On Tue, Apr 19, 2016 at 12:30 PM, Bruno Marchal   
wrote:

​
​> ​"is" in which sense?

​"​sense" in which sense? ​You must be a fan of Bill Clinton  
who notoriously said in answer to a question in a legal deposition:

  ​
"It depends on what the meaning of the word 'is' i​s."​

​> ​Some multi or multimulti verses could be everything physical  
that there is, but not everything needs to be physical


​But physicists deal in the physical that why they're bored to  
tears when people start talking about what things would look like  
from places that are impossible to exist even in theory.  ​


​> ​exemple: the natural numbers, the complex numbers,

​First of all we don't even know for certain that the Real Numbers  
exist much less the ​ Complex Numbers, and even it they do they  
don't have a location. but a viewpoint ​does, it's a position of  
observation​; ​and if that location is not inside the multiverse  
it does not exist.


​> ​but logically, it is conceivable to have structure containing  
themselves,


​Fine, but it is not logical to have something that is not part of  
itself be part of itself; like a place that is not part of the  
multiverse you can ​stand on to look at it from the outside. The  
multiverse has no outside.


That is why Nagel called it the point of view of nowhere, and  
sometimes I call something slightly similar the 0th person point of  
view. What you say does not refute what I said, given that here, the  
0th point of view is given by the mathematics of the Everett Universal  
Wave. It just means that we look at the wave function of the universe  
assuming QM without collapse. And I have not use this, only any  
superposition coming from Alice and Bob entangling themselves with a  
singlet state (sometehing you have eliminate from the successive  
quotes, so we were leading astray from the topic).


Bruno




​>> ​If the works of​ Galilee, Einstein​ or​ Maxwell​  
were built on unphysical foundation​s​ then today nobody would  
remember their names, instead they are among the most ​famous​  
physicists of all time. In fact Einstein came up with relativity by  
trying to imagine what the viewpoint would be of somebody moving at  
the speed of light and ​​discovered that viewpoint would produce  
logical contradictions​,​ and therefore CAN NOT EXIST.


​> ​No, he put itself at the place of a photon which does move at  
the speed of light, and concluded to the laws of relativity and to  
the fact that the photon can't have a mass non null. I think.


​Einstein figured that ​if the fundamental laws of physics were  
worth anything then they must be true for any frame of reference,  
but from the frame of reference of somebody moving at 186,000 miles  
a second all electromagnetic waves would have a undulating shape  
that changes in space but not in time and light would have zero  
velocity. But that would be contrary to Maxwell's equations,  
therefore Einstein concluded that the viewpoint of a observer moving  
at 186,000 miles a second CAN NOT EXIST. And after that realization  
the rest of special relativity fell into place.


​> ​Many works of many physicists are built in part (at least) on  
unphysical foundation: mathematics.


I can't think of one. It's true that before Einstein proved them  
wrong people though non-Euclidean geometry was unphysical, but a  
place to stand outside the multiverse will always be unphysical  
because if it was physical it would be inside the multiverse.


 John k Clark





--
You received this message because you are subscribed to the Google  
Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it,  
send an email to everything-list+unsubscr...@googlegroups.com.

To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.


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



--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Bruce Kellett]

On 20/04/2016 3:21 pm, smitra wrote:

On 20-04-2016 03:02, Bruce Kellett wrote:

On 20/04/2016 6:56 am, smitra wrote:
The mistake made is to invoke classical reasoning after the 
measurements are made. If the choice for the orientation of the 
polarizers were not made in advance, then Alice and Bob cannot have 
said to have made any definite choices at all.


I think you need to learn something about decoherence , and the
emergence of the 'classical' from the 'quantum'. In the final
analysis, Alice and Bob meet to compare their results. By that stage,
their results, and their relative magnet orientations, are definite
and classical (FAPP if you wish). And that is the end result we have
to explain. All else is boondoggle.


Invoking FAPP is precisely where your argument goes wrong.


Actually, I think that in order for MWI to make any sense at all, the 
separation of worlds has to be absolute, not just FAPP -- but that is 
another argument.


While due to decoherence the macroscopic world looks classical, in 
reality (assuming MWI)  it not classical. This means that when Bob 
meets with Alice that the settings Alice chose are still not 
determined. It is only when Alice communicates to Bob what her 
polarizer settings were


If Alice's setting are not determined, how can she communicate to Bob 
what they were? Decoherence works for both Alice and Bob separately, and 
long before they meet. Both have definite magnet settings and definite 
results by then -- that is decoherence at work.
that Bob becomes localized in that particular sector of the multiverse 
where this is now fixed.


So, decoherence ensures that long before A and B meet, there are only 
ffour worlds in the general case, ++, +-, -+, and --. It is the fact 
these these possibilities have different probabilities that is to be 
explained, and you have not explained that.


If Bob were to be imagined being located in that particular branch 
were Alice had made definite choices and had made definite 
observations, then that implies the existence of an observable for Bob 
that only acts on himself that will yield the exact details of what 
Alice has done. So, Bob could in principle have psychic powers, the 
information of what Alice did would already be present in his brain 
before Alice communicates these to him!


No it doesn't.

Obviously, Bob's brain does not have any information about what Alice 
did until the details are communicated to him. So, Bob's mind is 
identical across the many branches where Alice and, due to 
decoherence, the local environment is different. So, in the experiment 
the effectively classical communication is not at all trivial, in the 
MWI it is a crucial step localizing the observers in the multiverse as 
where the measurements of the spins.


So classical communication has quantum effects? It is the classical 
communication that 'causes' the EPR correlations? What about the effect 
of the entangled spins -- that is purely quantum, and that gives rise to 
the quantum correlations.


What is your reactions to Maudlin's comment 
(https://arxiv.org/abs/1408.1826)


"Finally, there is one big idea. Bell showed that measurements made far 
apart cannot regularly display correlations that violate his inequality 
if the world is local. But this requires that the measurements have 
results in order that there be the requisite correlations. What if no 
“measurement” ever has a unique result at all; what if all the “possible 
outcomes” occur? What would it even mean to say that in such a situation 
there is some correlation among the “outcomes of these measurements”?


"This is, of course, the idea of the Many Worlds interpretation. It does 
not refute Bell’s analysis, but rather moots it: in this picture, 
phenomena in the physical world do not, after all, display correlations 
between distant experiments that violate Bell’s inequality, somehow it 
just seems that they do. Indeed, the world does not actually conform to 
the predictions of quantum theory at all (in particular, the prediction 
that these sorts of experiments have single unique outcomes, which 
correspond to eigenvalues), it just seems that way. So Bell’s result 
cannot get a grip on this theory.


"That does not prove that Many Worlds is local: it just shows that 
Bell’s result does not prove that it isn’t local. In order to even 
address the question of the locality of Many Worlds a tremendous amount 
of interpretive work has to be done. This is not the place to attempt 
such a task"


Bruce

Microsoft Word - What Bell Did revised.docx

--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[smitra]

On 20-04-2016 03:02, Bruce Kellett wrote:

On 20/04/2016 6:56 am, smitra wrote:
The mistake made is to invoke classical reasoning after the 
measurements are made. If the choice for the orientation of the 
polarizers were not made in advance, then Alice and Bob cannot have 
said to have made any definite choices at all.


I think you need to learn something about decoherence , and the
emergence of the 'classical' from the 'quantum'. In the final
analysis, Alice and Bob meet to compare their results. By that stage,
their results, and their relative magnet orientations, are definite
and classical (FAPP if you wish). And that is the end result we have
to explain. All else is boondoggle.


Invoking FAPP is precisely where your argument goes wrong. While due to 
decoherence the macroscopic world looks classical, in reality (assuming 
MWI)  it not classical. This means that when Bob meets with Alice that 
the settings Alice chose are still not determined. It is only when Alice 
communicates to Bob what her polarizer settings were that Bob becomes 
localized in that particular sector of the multiverse where this is now 
fixed.


If Bob were to be imagined being located in that particular branch were 
Alice had made definite choices and had made definite observations, then 
that implies the existence of an observable for Bob that only acts on 
himself that will yield the exact details of what Alice has done. So, 
Bob could in principle have psychic powers, the information of what 
Alice did would already be present in his brain before Alice 
communicates these to him!


Obviously, Bob's brain does not have any information about what Alice 
did until the details are communicated to him. So, Bob's mind is 
identical across the many branches where Alice and, due to decoherence, 
the local environment is different. So, in the experiment the 
effectively classical communication is not at all trivial, in the MWI it 
is a crucial step localizing the observers in the multiverse as where 
the measurements of the spins.


Saibal







Bruce

In some particular sector where Alice made some particular result and 
found some particular result, she knows that Bob's spin state. But Bob 
lives in larger sector of the multiverse which includes sectors where 
Alic had made different choices.


 Alice and Bob communicating later is not some trivial exchange of 
information that existed a priori, it leads to a  further de-facto 
collapse of the wavefunction.


There isn't anything more to this that Alice measuring the spin of an 
electron in a lab, and then letting Bob who doesn't know what 
direction the spin was measured in, doing another measurement.


Saibal


--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Bruce Kellett]

On 20/04/2016 6:56 am, smitra wrote:
The mistake made is to invoke classical reasoning after the 
measurements are made. If the choice for the orientation of the 
polarizers were not made in advance, then Alice and Bob cannot have 
said to have made any definite choices at all.


I think you need to learn something about decoherence , and the 
emergence of the 'classical' from the 'quantum'. In the final analysis, 
Alice and Bob meet to compare their results. By that stage, their 
results, and their relative magnet orientations, are definite and 
classical (FAPP if you wish). And that is the end result we have to 
explain. All else is boondoggle.


Bruce

In some particular sector where Alice made some particular result and 
found some particular result, she knows that Bob's spin state. But Bob 
lives in larger sector of the multiverse which includes sectors where 
Alic had made different choices.


 Alice and Bob communicating later is not some trivial exchange of 
information that existed a priori, it leads to a  further de-facto 
collapse of the wavefunction.


There isn't anything more to this that Alice measuring the spin of an 
electron in a lab, and then letting Bob who doesn't know what 
direction the spin was measured in, doing another measurement.


Saibal


--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Bruce Kellett]

On 20/04/2016 7:05 am, Jesse Mazer wrote:
On Tue, Apr 19, 2016 at 12:06 AM, Bruce Kellett 
> wrote:


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?



If the probability of them selecting each possible detector setting on 
this single measurement is the same as the frequency with which they 
would select each detector setting on a large number of trials, then 
the statistics of results will also be the same.


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?


Within the context of the simulation, they are measuring the two 
members of an entangled pair. But the computer doesn't use any 
*actual* input from real-world instruments measuring entangled 
particle pairs, all computations and inputs are classical ones.


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.



That's true, the point here is just that you can generate these 
statistics using what I would define to be a "local" set of rules (see 
the bottom of this message for a discussion of what I understand 
'local' rules to mean), and each copy has the *experience* of making 
only a single measurement and getting a single reported measurement 
from the other experimenter.




But it is absolutely crucial that the relevant pairing information be 
retained. In other words, we have to know which Alice measurement 
corresponds to the Bob measurement on /t//hat particular///entangled 
pair. If that pairing information is lost, or not available, then your 
toy model is not simulating the EPR set up, and so is useless.


In this case, what is being simulated is only a *single* entangled 
pair, not multiple entangled pairs. Alice measures her member of the 
simulated pair at a single moment and some copies get one result and 
some copies get a different result at that moment, and likewise Bob 
measures his member of the simulated pair at a position and time with 
a spacelike separation from Alice's measurement, and some of his 
copies at that position get one result and some get a different result.


--the computers simulating Alice has to assign the number of copies 
that see each possible result without any foreknowledge of what 
happened with Bob, and vice versa. If Bob is scheduled to transmit 
his result to Alice at a particular time, then the computer 
simulating Bob actually sends a package of messages from the 
different copies of Bob, this message traveling to the computer 
simulating Alice at the speed of light. When the computer 

Re: Cryonics punched cards and the brain

[John Clark]

On Tue, Apr 19, 2016 at 12:30 PM, Bruno Marchal  wrote:
​

> ​> ​
> "is" in which sense?
>

​"​sense" in which sense?

​You must be a fan of Bill Clinton who notoriously said in answer to a
question in a legal deposition:
  ​
"It depends on what the meaning of the word 'is' i
​s."​



> ​> ​
> Some multi or multimulti verses could be everything physical that there
> is, but not everything needs to be physical
>

​But physicists deal in the physical that why they're bored to tears when
people start talking about what things would look like from places that are
impossible to exist even in theory.  ​


> ​> ​
> exemple: the natural numbers, the complex numbers,
>

​First of all we don't even know for certain that the Real Numbers exist
much less the ​

Complex Numbers, and even it they do they don't have a location. but a
viewpoint ​does, it's a
position of observation
​; ​and if that location is not inside the multiverse it does not exist.


> ​> ​
> but logically, it is conceivable to have structure containing themselves,
>

​Fine, but it is not logical to have something that is not part of itself
be part of itself; like a place that is not part of the multiverse you can
​stand on to look at it from the outside. The multiverse has no outside.


​>> ​
>> If the works of
>> ​
>> Galilee, Einstein
>> ​
>> or
>> ​
>> Maxwell
>> ​
>> were built on unphysical foundation
>> ​s​
>> then today nobody would remember their names, instead they are among the
>> most
>> ​famous​
>>  physicists of all time. In fact Einstein came up with relativity by
>> trying to imagine what the viewpoint would be of somebody moving at the
>> speed of light and
>> ​​
>> discovered that viewpoint would produce logical contradictions
>> ​,​
>> and therefore CAN NOT EXIST.
>
>
> ​> ​
> No, he put itself at the place of a photon which does move at the speed of
> light, and concluded to the laws of relativity and to the fact that the
> photon can't have a mass non null. I think.
>

​Einstein figured that ​if the fundamental laws of physics were worth
anything then they must be true for any frame of reference, but from the
frame of reference of somebody moving at 186,000 miles a second all
electromagnetic waves would have a undulating shape that changes in space
but not in time and light would have zero velocity. But that would be
contrary to Maxwell's equations, therefore Einstein concluded that the
viewpoint of a observer moving at 186,000 miles a second CAN NOT EXIST. And
after that realization the rest of special relativity fell into place.

​> ​
> Many works of many physicists are built in part (at least) on unphysical
> foundation: mathematics.
>

I can't think of one. It's true that before Einstein proved them wrong
people though non-Euclidean geometry was unphysical, but a place to stand
outside the multiverse will always be unphysical because if it was physical
it would be inside the multiverse.

 John k Clark

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Aharanov-Bohm non-locality is an artifact of invoking classical potentials

[smitra]

The real world is quantum-mechanical, no classical. At the macroscopic 
level, quantum mechanics does not become equivalent to classical physics 
at all (there is no way an infinite dimensional Hilbert space will 
somehow reduce to a classical phase space), what happens is that the 
results of computations can be performed by pretending that classical 
mechanics is correct, with impunity.


So, whenever classical concepts are introduced, the results may be good 
enough for the physical quantities that one computes, for 
interpretational issues there can be problems.



As pointed out by Vaidman here:

http://arxiv.org/abs/1110.6169

This is also the case for the Aharonov-Bohm effect. So, the effect is 
obviously real, but the purported non-locality is just an artifact of 
classical reasoning.


Saibal

--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Jesse Mazer]

On Tue, Apr 19, 2016 at 12:06 AM, Bruce Kellett 
wrote:

> 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?
>


If the probability of them selecting each possible detector setting on this
single measurement is the same as the frequency with which they would
select each detector setting on a large number of trials, then the
statistics of results will also be the same.



> 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?
>

Within the context of the simulation, they are measuring the two members of
an entangled pair. But the computer doesn't use any *actual* input from
real-world instruments measuring entangled particle pairs, all computations
and inputs are classical ones.



> 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.
>


That's true, the point here is just that you can generate these statistics
using what I would define to be a "local" set of rules (see the bottom of
this message for a discussion of what I understand 'local' rules to mean),
and each copy has the *experience* of making only a single measurement and
getting a single reported measurement from the other experimenter.



>
>
> 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 

Re: Non-locality and MWI

[smitra]

The mistake made is to invoke classical reasoning after the measurements 
are made. If the choice for the orientation of the polarizers were not 
made in advance, then Alice and Bob cannot have said to have made any 
definite choices at all. In some particular sector where Alice made some 
particular result and found some particular result, she knows that Bob's 
spin state. But Bob lives in larger sector of the multiverse which 
includes sectors where Alic had made different choices.


 Alice and Bob communicating later is not some trivial exchange of 
information that existed a priori, it leads to a  further de-facto 
collapse of the wavefunction.


There isn't anything more to this that Alice measuring the spin of an 
electron in a lab, and then letting Bob who doesn't know what direction 
the spin was measured in, doing another measurement.


Saibal


On 16-04-2016 02:33, Bruce Kellett wrote:

On 16/04/2016 12:20 am, Bruno Marchal wrote:


On 14 Apr 2016, at 14:31, Bruce Kellett wrote:


Although all possible combinations of measurement outcomes exist
in MWI, it is not clear what limits the results of the two
observers to agree with quantum mechanics when they meet up in
just one of the possible worlds.


Because they have separated locally, and Alice's measurement just
inform both of them (directly for Alice and indirectly for Bob once
some classical bit of information is communicated by Alice to Bob by
the usual means).


 This is the purported solution given by Deutsch and Hayden, amongst
many others. Unfortunately, it does not work, as can be demonstrated
by working through a specific example.

 Consider the usual case of a spin singlet that splits into two
spin-half components that separate and are measured by A and B at
spacelike separation. There are two possible measurement results for
each observer, call them |+> and |->. The entangled state can then be
written as:

|psi> = (|+>|-> - |->|+>).

 ignoring normalization factors for simplicity. The first ket applies
to observer A and the second to observer B.

 This is the general expression for the singlet state in any basis,
such as would be define by the orientation of the measuring magnets.
We denote the measurement results in some other direction as |+'> and
|-'>.

 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 these four worlds is equally likely.

 But this conclusion is contradicted by quantum mechanics: if the two
observers, by chance, have their magnets aligned, then the |+>|+'> and
|->|-'> combinations are impossible. In general, the probabilities of
the four possible joint outcomes depend explicitly on the relative
orientation of the magnets of the A and B -- they are seldom all
equal. How is this taken into account in the formalism?

 In the formalism of QM, the answer is clear enough. Given the
expression for |psi> in an arbitrary basis, as above, we can choose
the basis for this expansion to be that for the orientation of magnet
A. But then, in order to get the relevant outcomes for B, we have to
rotate this expansion to the basis corresponding to the orientation of
magnet B. But we have to do this rotation before B makes his
measurement! How does B know the necessary rotation angle? Recall that
both A and B make independent arbitrary rotations at spacelike
separations.

 After the measurements are complete, A and B communicate their
results to each other, so the branch of B that measured |+'>
communicates this to both copies of A, to get the combinations |+>|+'>
and |->|+'>. Similarly, the branch of B that got the result |-'>
communicates this to both copies of A, to get the remaining two
combinations |+>|-'> and |->|-'>. Deutsch and Hayden propose that
non-locality is eliminated by B communicating his orientation angle as
well as his result to A. But adding the angle theta to the information
transmitted does not change the fact that one copy of B transmits a
|+'> result and one copy transmits a |-'> result. In other words, this
extra orientation information is completely irrelevant to the outcomes
of the measurements, and also irrelevant to the relatives
probabilities for the our possible worlds.

 Deutsch and Hayden have not shown that this EPR experiment is local
in MWI -- they still have to use the rotation of the wave function
basis for B's measurement _before_ that measurement is made, and that
information is not locally available to B, it can only have been
transmitted non-locally.

 So MWI does not give a local account of the EPR results on entanged
states.

 Bruce

 --
 You received this message because you are subscribed to 

Re: Cryonics punched cards and the brain

[Bruno Marchal]

On 18 Apr 2016, at 01:37, John Clark wrote:


On Sun, Apr 17, 2016  Bruno Marchal  wrote:
.
​>> ​​It's not just that you don't have to, you CAN'T do ​ 
theoretical physics​ from a viewpoint that CAN NOT EXIST because  
the result would be ridiculous and useless.


​>​It does not exist physically, but it can still exist  
mathematically, logically, etc.


​If the multiverse contains everything that there is



"is" in which sense? Some multi or multimulti verses could be  
everything physical that there is, but not everything needs to be  
physical (exemple: the natural numbers, the complex numbers, the  
differentiable varieties, the topological groups, the Kripke  
relational structures, etc.).
many cosmologists try to figure out what could be the complete picture  
of the physical reality, and some people serach this for the whole of  
reality: physical and non physical.




then there is nothing logical about talking about what things would  
look like ​for somebody standing outside the multiverse looking  
back at it.​ It's a ridiculous ​waste of time, a complete dead  
end.​


Yet the term "multiverse" itself refers to such an object.

here you assume some realm which cannot belong to itself, which I  
appreciate (actually), but logically, it is conceivable to have  
structure containing themselves, and that is the case for some set  
theories, where the universe of all sets is itself a set (like with  
Quine's NF).


You are just choosing a special philosophy among an infinity which  
suits your point, but that is not proving anything, and certainly not  
a rebuttal of what I said.








​>> ​if you start with a unphysical premise then you will reach a  
unphysical conclusion and that does neither mathematicians nor  
physicists any good.


​> ​That would make disappear a lot of thought experience which  
have play an important role in the advance in physics (in Galilee,  
Einstein, Maxwell, etc.).


If the works of​ Galilee, Einstein​ or​ Maxwell​ were built  
on unphysical foundation​s​ then today nobody would remember  
their names, instead they are among the most ​famous​ physicists  
of all time. In fact Einstein came up with relativity by trying to  
imagine what the viewpoint would be of somebody moving at the speed  
of light and ​​discovered that viewpoint would produce logical  
contradictions​,​ and therefore CAN NOT EXIST.


No, he put itself at the place of a photon which does move at the  
speed of light, and concluded to the laws of relativity and to the  
fact that the photon can't have a mass non null. I think.


Many works of many physicists are built in part (at least) on  
unphysical foundation: mathematics.


Bruno




​ John K Clark​






--
You received this message because you are subscribed to the Google  
Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it,  
send an email to everything-list+unsubscr...@googlegroups.com.

To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.


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



--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

R: Re: Non-locality and MWI

['scerir' via Everything List]

Spudboy100:
"Brent, to be more precise, I was thinking that every photon event staring from 
1 nanosecond ago, on backwards, might still be floating around somewhere. I am 
wondering also if this data is accessible, in principle?" This reminds me of an 
old quote: "It is sufficient to destroy

the
interference pattern, if the path information is accessible in principle from
the

experiment
or even if it is dispersed in the environment and beyond any technical

possibility
to be recovered, but in principle 'still out there'."





-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Brent Meeker]

On 4/19/2016 6:00 AM, spudboy100 via Everything List wrote:
Brent, to be more precise, I was thinking that every photon event 
staring from 1 nanosecond ago, on backwards, might still be floating 
around somewhere.


The photons may have been interacted with atoms and lost, but if QM is 
strictly unitary the information still exists in principle - it's just 
inaccessible FAPP.


Brent

--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI (literature)

[Bruno Marchal]

On 19 Apr 2016, at 13:10, 'scerir' via Everything List wrote:

BTW, surprisingly  the debate about the real meaning of (the two)  
Bell’s theorems
(locality, local causality, predetermination, predictability,  
separability, determinism,

counterfactual definiteness, realism,  etc.) is still going on ...

Here is some (very short) literature

J.S. Bell’s Concept of Local Causality
Travis Norsen
https://arxiv.org/pdf/0707.0401v3

Local Causality and Completeness: Bell vs. Jarrett
Travis Norsen
https://arxiv.org/abs/0808.2178

Does quantum nonlocality irremediably conflict with Special  
Relativity?

GianCarlo Ghirardi
https://arxiv.org/abs/0912.0177

The Two Bell's Theorems of John Bell
Howard M. Wiseman
https://arxiv.org/abs/1402.0351

Causarum Investigatio and the Two Bell's Theorems of John Bell
Howard M. Wiseman, Eric G. Cavalcanti
https://arxiv.org/abs/1503.06413

Are there really two different Bell's theorems?
Travis Norsen
https://arxiv.org/abs/1503.05017

Reply to Norsen's paper "Are there really two different Bell's  
theorems?"

Howard M. Wiseman, Eleanor G. Rieffel
https://arxiv.org/abs/1503.06978

What Bell Did
Tim Maudlin
https://arxiv.org/abs/1408.1826



Tim Maudlin is good on this subject. He wrote also an excellent (imo)  
book on non-locality ("Quantum Non-Locality & Relativity" . I share  
all its conclusions there, and in this paper too, except what I have  
put, below,  in bold-underline (which I would replace by the fact that  
we need "only" some technical treatment of the first and third person  
pov distinction, but that is what computer science and mathematical  
logic offer on a plate (with the second recursion theorem notably)  
(and with the measure problem as a gift, of course).




(Sorry for the bad format): Tim wrote:


<>

Bruno




Reply to Werner
Tim Maudlin
https://arxiv.org/abs/1408.1828

What Maudlin replied to
R. F. Werner
https://arxiv.org/abs/1411.2120




--
You received this message because you are subscribed to the Google  
Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it,  
send an email to everything-list+unsubscr...@googlegroups.com.

To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.


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



--
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[spudboy100 via Everything List]

Brent, to be more precise, I was thinking that every photon event staring from 
1 nanosecond ago, on backwards, might still be floating around somewhere. I am 
wondering also if this data is accessible, in princple? Yes, the bright stuff 
from some quasar 5 billion years ago, but maybe also a bird chirping on a 
branch from 1811, by a stream near Bangalore. Less luminescence, yet still 
photonically interactive. This may be a conceptual dead end in physics and 
astronomy and perhaps mathematics. 


-Original Message-
From: Brent Meeker 
To: everything-list 
Sent: Tue, Apr 19, 2016 12:58 am
Subject: Re: Non-locality and MWI

?? 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.

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.

Re: Non-locality and MWI

[Bruno Marchal]

On 19 Apr 2016, at 02:08, Bruce Kellett wrote:


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.


OK.






Note that this says nothing about collapse or not, about one or many  
worlds, or about any interpretational issues.


More or less OK? but then you take QM without collapse. Copenhague put  
the collapse in the axioms. Everett withdrew it. That are two  
different theories. Then, if you define a world by a set of events  
close for intrecation: non collapse entails many worlds, independently  
of the interpretations. It is a point where I geree with Deustch: QM  
without collapse is a theory of many-worlds, or many (possibly  
superposed) states.






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.


Bt the collapse theory is too fuzzy to make specific predictions, and  
when they do, they are contradicted by the experiments. There are not  
yet one evidence for the collapse of the wave, and without collapse,  
we keep the superposition (many-worlds) intact.








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.



Sorry, but in logic, such notion, like theories and interpretation is  
the very subject of study.


In this case we have three theories:

1) SWE + collapse + dualist theory of measurement/mind   (copenhagen)

2) SWE + Mechanism

3) Mechanism

The corresponding interpretations are

1) A unique physical reality (and a strange non local and magical  
association with mind)


2) a multiverse

3) a multidream (which exists provably in arithmetic, if we assume  
mechanism)






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.


Yes, but they have been multiplied. They each observe one result, like  
their counterparts, but in their independent branches, the results are  
correlated.



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.


Then you are introducing a collapse, and are changing of 

Non-locality and MWI (literature)

['scerir' via Everything List]

BTW, surprisingly  the debate about the real meaning of (the two) Bell’s 
theorems
(locality, local causality, predetermination, predictability, separability, 
determinism,
counterfactual definiteness, realism,  etc.) is still going on ...

Here is some (very short) literature

J.S. Bell’s Concept of Local Causality

Travis Norsen

https://arxiv.org/pdf/0707.0401v3



Local Causality and Completeness: Bell vs. Jarrett

Travis Norsen 

https://arxiv.org/abs/0808.2178



Does quantum nonlocality irremediably conflict with Special Relativity?

GianCarlo Ghirardi

https://arxiv.org/abs/0912.0177



The Two Bell's Theorems of John Bell

Howard M. Wiseman

https://arxiv.org/abs/1402.0351



Causarum Investigatio and the Two Bell's Theorems of John Bell

Howard M. Wiseman, Eric G. Cavalcanti

https://arxiv.org/abs/1503.06413



Are there really two different Bell's theorems? 

Travis Norsen

https://arxiv.org/abs/1503.05017



Reply to Norsen's paper "Are there really two different Bell's theorems?" 

Howard M. Wiseman, Eleanor G. Rieffel 

https://arxiv.org/abs/1503.06978



What Bell Did

Tim Maudlin

https://arxiv.org/abs/1408.1826



Reply to Werner

Tim Maudlin

https://arxiv.org/abs/1408.1828



What Maudlin replied to

R. F. Werner

https://arxiv.org/abs/1411.2120






-- 
You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to everything-list+unsubscr...@googlegroups.com.
To post to this group, send email to everything-list@googlegroups.com.
Visit this group at https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.