No drama quantum electrodynamics? (was: Local realism ruled out?)

[akhmeteli]

As the only thread I've ever started before (https://www.physicsforums.com/showthread.php?t=369328 ) attracted a lot of interest, became one of the most viewed threads in the forum, and was closed :-), I'd like to make a short update here.

I have published a new article on the topic: "No drama quantum electrodynamics?", European Physical Journal C, (2013) 73:2371 (http://link.springer.com/content/pdf/10.1140/epjc/s10052-013-2371-4.pdf - open access).

Abstract:

This article builds on recent work (Akhmeteli in Int. J. Quantum Inf. 9(Supp01):17, 2011; J. Math. Phys. 52:082303, 2011), providing a theory that is based on spinor electrodynamics, is described by a system of partial differential equations in 3+1 dimensions, but reproduces unitary evolution of a quantum field theory in the Fock space. To this end, after introduction of a complex four-potential of electromagnetic field, which generates the same electromagnetic fields as the initial real four-potential, the spinor field is algebraically eliminated from the equations of spinor electrodynamics. It is proven that the resulting equations for electromagnetic field describe independent evolution of the latter and can be embedded into a quantum field theory using a generalized Carleman linearization procedure. The theory provides a simple and at least reasonably realistic model, valuable for interpretation of quantum theory. The issues related to the Bell theorem are discussed.

 

[fzero]

Since you claim this is about a quantum theory, can you show that this theory has no negative-norm states? With a complex gauge field, the gauge symmetry can only remove the real part of the longitudinal degrees of freedom. It doesn't seem that the quantum theory exists.

Maybe a more basic question, but what happens if there is more than one matter field? What about chiral matter?

 

[akhmeteli]

Since you claim this is about a quantum theory, can you show that this theory has no negative-norm states?

Not sure I fully understand. There are actually two different theories related to spinor electrodynamics in my article. One of them, a "small" theory, is largely equivalent to spinor electrodynamics, so if something's wrong with this "small" theory, something's wrong with spinor electrodynamics as well. This "small" theory is embedded into a "large" quantum theory in the Fock space. I am not sure there are negative-norm states in the Fock space. Furthermore, if there were indeed negative-norm states in this "large" theory, I am not sure that would be my problem, as I am only interested in the "small" theory, and the only states of the "large" theory that have their match in the "small" theory are the functional coherent states, which have non-negative norm.

With a complex gauge field, the gauge symmetry can only remove the real part of the longitudinal degrees of freedom. It doesn't seem that the quantum theory exists.

Again, not sure I fully understand. It is my understanding that the longitudinal degrees of freedom are typically discussed in the context of the Lorenz gauge (in other gauges these degrees of freedom are typically not separated from the other degrees of freedom), and I don't use the Lorenz gauge. And again, the "small" theory, while uses complex potentials (note, by the way, that arbitrary complex potentials are not allowed in the "small" theory), is largely equivalent to spinor electrodynamics.

Maybe a more basic question, but what happens if there is more than one matter field? What about chiral matter?

I believe this problem is partly solved. Initially the results were obtained for scalar electrodynamics (in my IJQI article - http://akhmeteli.org/akh-prepr-ws-ijqi2.pdf ), where there is just one matter field with one component. The results for spinor electrodynamics offered in that older article were not very satisfactory, as generally you can make only one component of the Dirac spinor real with a gauge transform. However, I showed in my JMP article (http://akhmeteli.org/wp-content/uploads/2011/08/JMAPAQ528082303_1.pdf ) that, surprisingly, three out of four components of the Dirac spinor can be algebraically eliminated from the Dirac equation, and it is obvious that the remaining component can be made real by a gauge transform. That opened the way for the results of the EPJC article. So I am not sure there is really more than one matter field in Nature. What we typically consider as different matter fields can be just different components of a representation of some group, so it is not obvious that the procedure of my articles cannot be implemented if the number of the components is greater than four. Remember that, while the number of different matter fields is much greater in the Standard Model than in quantum electrodynamics, the choice of gauge is also much richer in the former theory than in the latter one. So while I don't know if similar results can be obtained for the Standard Model or some GUT, it is not obvious that they cannot.

 

[ftr]

akhmeteli, can you then make the Noether current real and recover probabilistic interpretation(in QFT). I am not also clear if you are saying that your system solves (or clarifies it) the measurement problem or not.

 

[akhmeteli]

akhmeteli, can you then make the Noether current real

I do use the "generalized gauge transform", but I don't claim invariance under such transform, so I only have real Noether current.

and recover probabilistic interpretation(in QFT).

I recover unitary evolution of a quantum field theory. It is my understanding that, say, the Born rule is a great approximation, but still an approximation, if unitary evolution is precise. Such understanding is based on the results of Allahverdyan ea. (http://arxiv.org/abs/1107.2138, Phys. Rep. 525, 1 (2013)).

I am not also clear if you are saying that your system solves (or clarifies it) the measurement problem or not.

I don't think my work solves the measurement problem. My position is that, strictly speaking, the measurement problem just cannot be solved, as unitary evolution and the theory of quantum measurements contradict each other. On the other hand, the theory of quantum measurements, at least, in some cases, can be derived from unitary evolution as some approximation (again, please see the work by Allahverdyan ea.) Therefore, I try to take care of unitary evolution and reject the theory of quantum measurements as a precise theory, hoping that the measurement problem will take care of itself :-) (at the level of approximations). Does this qualify as "clarification"? You decide.

 

[DrChinese]

The issues related to the Bell theorem are discussed.

You are being a bit generous here (and as well in your paper). The only discussion of Bell is to dismiss it as requiring "...mutually contradictory assumptions..." You may as well have left this line of reasoning out completely. Or more factually, simply state that your ideas contradict Bell completely.

You also cite the lack of a loophole-free experimental test as evidence that local realism is not ruled out by Bell tests. I assume you are aware that the loopholes have been individually closed. It is a stretch, to say the least, to assert this is any kind of reason to believe test results are not representative. We could say the same thing about ANY physical test, including those regarding the speed of light or any other measurable constant - which certainly have not had "loophole-free" tests.

 

[DevilsAvocado]

“While the Bell inequalities cannot be violated in the theories of Ref. [1], there are some reasons to believe these inequalities cannot be violated either in experiments or in quantum theory: on the one hand, there is no loophole-free experimental evidence of violations of the Bell inequalities (see, e.g., Ref. [2]), on the other hand, to prove that the inequalities can be violated in quantum theory, one needs to use the theory of quantum measurements, e.g., the projection postulate.”

Objections from a layman:

• Ref. [1]? Where is it? What is it? What does it prove?
• Are you claiming that Zeilinger, in Ref. [2], is stating that all experiments performed by him will most probably not work once all loopholes are closed simultaneously?? Or is he saying the opposite?
• “on the other hand, to prove that the inequalities can be violated in quantum theory, one needs to use the theory of quantum measurements, e.g., the projection postulate” – Says who? Proven by what??
• Projection postulate? Please excuse a layman if I’m wrong; but QM theory doesn’t say anything about what happens at measurement (I think it’s titled “The Measurement Problem” by the way), and that’s the sole reason we have all this philosophical interpretation business going on. If this was perfectly clear from QM theory, interpretations would all be dead by now (except maybe one). Does anyone use von Neumann's projection postulate from the 1930s these days? Isn’t it completely overthrown??
• From QM theory – entanglement is all you need. The rest; Polarizers & Malus' law (from 1809), and Bell's theorem, has nothing to do with QM theory. I hope you’re not saying that entanglement is dependent on von Neumann's projection postulate??

... Schrödinger & Bell are probably turning in their graves already ...

 

[akhmeteli]

You are being a bit generous here (and as well in your paper). The only discussion of Bell is to dismiss it as requiring "...mutually contradictory assumptions..." You may as well have left this line of reasoning out completely. Or more factually, simply state that your ideas contradict Bell completely.

I agree that the discussion of the issues related to the Bell theorem is short. However, I refer the reader to a longer discussion in an earlier article in IJQI (http://akhmeteli.org/akh-prepr-ws-ijqi2.pdf ). I admit that I have little to add to that longer discussion. Furthermore, while "...mutually contradictory assumptions..." is called "only" in your book, it's "more than enough" in mine: according to formal logic, if you make two mutually contradictory assumptions, you can get any conclusion you want.

You also cite the lack of a loophole-free experimental test as evidence that local realism is not ruled out by Bell tests. I assume you are aware that the loopholes have been individually closed. It is a stretch, to say the least, to assert this is any kind of reason to believe test results are not representative.

As I said several times, until all assumptions of a theorem are fulfilled simultaneously, one cannot be sure that its conclusion holds. I asked you a few times: isn't your logic applicable to Euclidean geometry (https://www.physicsforums.com/showpost.php?p=2534347&postcount=34 )? Unless I missed something, you chose to ignore this question.

Another thing. According to Zeilinger and his collaborators (http://arxiv.org/abs/1212.0533 ), "The realization of an experiment that is free of all three assumptions - a so-called loophole-free Bell test - remains an important outstanding goal for the physics community", whereas for you everything is already crystal clear. I guess you would not fund such experiment as useless :-)

We could say the same thing about ANY physical test, including those regarding the speed of light or any other measurable constant - which certainly have not had "loophole-free" tests.

I admit I am a bit confused: does this mean that we should "peacefully coexist" with lousy physics, as all physics is lousy anyway? Let me just repeat that extraordinary claims, such as ruling out local realism, require extraordinary proof. If some other experiments are deficient, I am sure someone will raise the issue of such deficiency, whereas I have to discuss weak points of Bell experiments to anticipate criticism of my work.

 

[DrChinese]

1. Furthermore, while "...mutually contradictory assumptions..." is called "only" in your book, it's "more than enough" in mine: according to formal logic, if you make two mutually contradictory assumptions, you can get any conclusion you want.

2. Let me just repeat that extraordinary claims, such as ruling out local realism, require extraordinary proof.

1. True enough, but you are kidding yourself if you think you can dismiss Bell with this comment, and then claim you address Bell. Seriously? This is the first thing anyone is going to look at in a paper of this type.

2. There is no shortage of proof, just a shortage on your part to accept any of it. There isn't a hint that the QM cos^2(theta) rule for photons is incorrect. As experiments improve, the statistical deviation from the local realistic predictions (constrained of course by Bell) make that view MORE and MORE implausible. That is exactly the reverse of what would be expected by your position. And the comment that extraordinary claims require extraordinary proof is a meaningless application of Sagan's comments. Extraordinary is clearly in the eyes of the beholder.

I am shocked by your claim that you are discussing Bell in your paper. A more accurate summary would be that you dismiss Bell by assumption; that way the reader knows what they must also do to go along with your mechanism.

 

[jtbell]

General reminder: Please keep this discussion civil.

 

[DrChinese]

Akhmeteli,

Although I do not agree with some of what you are saying, I was pleased to see the paper expressing your ideas. Certainly no easy effort on your part.

-DrC

 

[glengarry]

It's pretty hard for me to understand the motivation behind this. In the heart of the argument, it seems, there lies a fundamental desire to "believe". In this case, the object of the belief happens to be the concept of local realism. In order to uphold this belief, I guess one must feel that, fundamentally, nature consists of nothing but material points. In order for this concept to be self consistent, matter must literally come in the form of mathematical points... that is, they must be zero dimensional.

The first reservation is simply this: in a three-dimensional universe, all objects that consist of less than three full dimensions cannot be said to exist. They simply cannot take any part in our reality. I can't really go any deeper with this part of the argument. It's just what *I* believe.

The next problem can be given a logical argument. Say there are two mathematical points approaching each other. At all times they are separated from each other by an infinite gap. (I say the gap is infinite, because in relation to an entity of zero measure, all other measures are infinite.) That is, except for one time... when they occupy the exact same location. There is no known form of mathematics that can handle this situation.

The only idea that can fully address these problems is to think of reality as consisting fundamentally of "space like" objects. It turns out that the wavefunction works out quite well for this situation. While it is true that all current forms of "accepted" physics do not postulate any forms of multi-dimensional objects in classical spacetime, the reason for this has nothing to do with whether or not these kinds of objects are a "good idea." IMO, it has everything to do with the fact that we are still a fairly young species that still has a long ways to go... both theoretically and experimentally.

I think there is no doubt that theorists will eventually start trying to somehow insert the wavefunction into the field of differential geometry. In fact, I am *always* doing this inside of my own head, and I am sometimes amazed by what I am able to visualize. But in terms of getting others to be interested in my, um, "visions"... I realize that I still have a very long ways to go. I know that I have to basically learn an entirely new language (diff. geom.), and I have to be able to speak it fluently.

Perhaps the best thing about string theory/M theory is that it is the first attempt to rigorously apply higher dimensional thinking to our understanding of the universe. But I feel it is too much of a slave to the particle ontology in order to be much use as a truly unifying paradigm. No matter. I am sure that the mathematical advances being made in that arena will go quite far when it comes to developing the kinds of theories that interest me.

So, it is important to understand that the point/location based approach of fundamental physical theory is on an inevitable march towards irrelevance... not simply because of the arguments that I outlined above. But rather because there is nowhere else we can go with it as a species. People are simply not inspired by it. Wavefunctions are beautiful. They are all about harmony. There's just no way to stop people from thinking that they are in integral part of our universe.

 

[akhmeteli]

1. True enough, but you are kidding yourself if you think you can dismiss Bell with this comment, and then claim you address Bell. Seriously? This is the first thing anyone is going to look at in a paper of this type.

I agree, the first question people ask looking at an article like that is "What about Bell?" But let me repeat that I include by reference the longer discussion of the issues related to Bell in my IJQI article. I just cannot repeat the same long discussion in every article on this topic. The most I can do is to offer a short summary.

Let me also emphasize that the longer discussion does not just "dismiss Bell". The logic there is (or can be) actually somewhat different. I say that one needs both unitary evolution and the projection postulate (theory of quantum measurements) to prove that the Bell inequalities can be violated in standard quantum theory. That means that if you adopt both unitary evolution and the projection postulate, you just cannot get a local realistic theory. You have to ditch one of the assumptions. Santos opined that we should ditch the theory of quantum measurements. And this is exactly what I do: I reject the theory of quantum measurements, at least as a precise theory. Then I successfully reproduce unitary evolution of a quantum field theory in a local realistic theory (by the way, this per se provides a no-go theorem: you cannot derive the Bell theorem using just unitary evolution, without the theory of quantum measurements). So I explicitly state which assumption of the Bell theorem I reject to escape the conclusion of the Bell theorem. Then I state (or could state) that this rejection is not deadly for my theory (for example, in comparison with experimental data) for two reasons: first, the projection postulate contradicts unitary evolution anyway, second, there is no experimental evidence of violations of the genuine Bell inequalities. It looks like such logic seems at least tolerable to some referees and readers of my articles. You don’t like such logic? This is regrettable, but unfortunately I just cannot write an article that everybody would like. Maybe next time :-)

2. There is no shortage of proof, just a shortage on your part to accept any of it. There isn't a hint that the QM cos^2(theta) rule for photons is incorrect.

There is no shortage of such hints, just a shortage on your part to accept any of it. This rule is a rule of the theory of quantum measurements (which, strictly speaking, contradicts unitary evolution), as it does not take into account unitary evolution of the total system including the photons and the instrument. Let me note that, strictly speaking, no measurement result is ever final (at least not in a limited volume with impenetrable walls) due to recurrence theorem, so how can your rule be precise? Let me also note that statements of the theory of quantum measurements are derived from unitary evolution in Allahverdyan’s article I quoted earlier, but as approximations, not as precise results. It turns out that there are even some subtle deviations from the Born rule! The derivation of their article was not reproduced for photons yet, but the contradiction between unitary evolution and the theory of quantum measurements exists for photons as well.

As experiments improve, the statistical deviation from the local realistic predictions (constrained of course by Bell) make that view MORE and MORE implausible. That is exactly the reverse of what would be expected by your position.

With all due respect, what statistical deviation from the local realistic predictions are you talking about? There have been no experimental evidence of violations of the genuine Bell inequalities so far, so there has been no evidence of “statistical deviation from the local realistic predictions”.

And the comment that extraordinary claims require extraordinary proof is a meaningless application of Sagan's comments.

His saying is famous enough, so I don’t think one can accuse me of plagiarism:-)

Extraordinary is clearly in the eyes of the beholder.

OK, then, so we just disagree on what is and what is not extraordinary.

I am shocked by your claim that you are discussing Bell in your paper. A more accurate summary would be that you dismiss Bell by assumption; that way the reader knows what they must also do to go along with your mechanism.

I respectfully disagree. You may say that I offer just a summary of discussion in this article, but there is a solid discussion in the IJQI article, and it is referenced in the latest article.

 

[akhmeteli]

It's pretty hard for me to understand the motivation behind this. In the heart of the argument, it seems, there lies a fundamental desire to "believe". In this case, the object of the belief happens to be the concept of local realism. In order to uphold this belief, I guess one must feel that, fundamentally, nature consists of nothing but material points. In order for this concept to be self consistent, matter must literally come in the form of mathematical points... that is, they must be zero dimensional.

If you are talking about my article, then I don't know how this is relevant, as I mostly consider fields, not particles.

 

[akhmeteli]

Akhmeteli,

Although I do not agree with some of what you are saying, I was pleased to see the paper expressing your ideas. Certainly no easy effort on your part.

-DrC

Thank you very much for the kind words. It was indeed difficult to obtain the mathematical results, but as for publishing them... Well, it was not a walk in the park, but I expected greater resistance to articles on this topic.

 

[DrChinese]

1. With all due respect, what statistical deviation from the local realistic predictions are you talking about? There have been no experimental evidence of violations of the genuine Bell inequalities so far, so there has been no evidence of “statistical deviation from the local realistic predictions”.

2. His saying is famous enough, so I don’t think one can accuse me of plagiarism:-)

1. Come on, the experiments have been run, published and been generally accepted. Need I post references?

The fact is, you believe there are definite values for spin components at all times - realism - and those values are independent of measurement context. Such values cannot maintain - relative to each other - the cos^2 rule. Bell shows this.


2. No plagarism, but technically the statement lacks merit. It is more of a guide, much like the dictum that you should accept the simpler explanation over the more complex one (Occam).

 

[akhmeteli]

1. Come on, the experiments have been run, published and been generally accepted. Need I post references?

It is my understanding that there has been no loophole-free experimental evidence of violations of the Bell inequalities. I don't believe you can post references to the contrary.

The fact is, you believe there are definite values for spin components at all times - realism - and those values are independent of measurement context.

I know that this is how realism is often defined in the context of quantum theory. Sometimes this "realism" is called "EPR realism". Actually, I don't believe in such "realism", and I stated that long ago (https://www.physicsforums.com/showpost.php?p=2534347&postcount=34 ): "As I tend to think Einstein was wrong about the uncertainty principle, I am not crying for that particular school." However, the notion of realism exists irrespective of quantum theory and means something different. Santos (http://arxiv.org/abs/quant-ph/0410193 , section II) illustrates this using the example of coin tossing: "head" state or "tail" state does not exist for a coin independently of the measurement procedure, even though the relevant measurement is classical. Another example: if you use the "EPR definition" of local realism, then classical electrodynamics is not local realistic. The models of my articles are similar to classical electrodynamics and are not "EPR realistic" either - the statement "there are definite values for spin components at all times" is not correct for them, but they are no less realistic than classical electrodynamics. Let me also add that the Bell theorem does not need to assume EPR realism (please see, e.g., Bell, Speakable and Unspeakable in Quantum Mechanics, Second Edition, Canbridge, Section 8, Locality in quantum mechanics:reply to critics)

2. No plagarism, but technically the statement lacks merit. It is more of a guide, much like the dictum that you should accept the simpler explanation over the more complex one (Occam).

So you actually demand that I give experimentalists and you some slack and ignore the loopholes:-). Sorry, I just cannot do that:-). I owe nobody that much. The issue is too important to cut corners.

 

[vanhees71]

In the Nature issue just published today, there is the claim of a Bell experiment with entangled photons which closes all loop-holes:

M. Giustina et al, Bell violation using entangled photons without the fair-sampling assumption, Nature 497, 227 (2013)
doi:10.1038/nature12012

Of course, sceptics, still adherent to socalled "local realistic models" could still argue that this is not an experiment that closes all loop-holes together but only the fair-sampling assumption. So today, there is not one single experiment that closes all loop-holes at the same time. But taken all experiments together you can say all loop-holes are closed.

Anyway, I think even if all loop-holes are closed, there's still the possibility open that there might be a non-local realistic model of nature, but as long as none is found, we better stick to quantum theory.

 

[Bryan Sanctuar]

Bell used the term beables (properties of a system that are not observed). In EM theory, E and H are beables but not the scalar and vector potential because of gauge invariance. However the introduction of spinors to me hold the key to realism, and locality.

Maybe some can help or comment: Bell's theorem is stated that LHV theories are ruled out. However Bell did not think the notion of non-locality to be reasonable. Rather the breakdown of local causality was an issue not with qm, but with Special Relativity. Is this an accurate view? (Bell wanted to do away with SR and find some aether frame which allows superluminal events).

 

[DrChinese]

In the Nature issue just published today, there is the claim of a Bell experiment with entangled photons which closes all loop-holes:

M. Giustina et al, Bell violation using entangled photons without the fair-sampling assumption, Nature 497, 227 (2013)
doi:10.1038/nature12012

------------------------------------

Here is the full version for post #18 above, in the archive:

http://arxiv.org/abs/1212.0533

 

[DrChinese]

Maybe some can help or comment: Bell's theorem is stated that LHV theories are ruled out. However Bell did not think the notion of non-locality to be reasonable.

Where have you seen this stated about Bell's position on non-locality? As far as I have read, he felt Bohmian type theories were good candidates.

 

[DevilsAvocado]

In the Nature issue just published today, there is the claim of a Bell experiment with entangled photons which closes all loop-holes:

M. Giustina et al, Bell violation using entangled photons without the fair-sampling assumption, Nature 497, 227 (2013)
doi:10.1038/nature12012

OMG! It could not have come at a more inappropriate time! Just as we thought there was a “definite maybe”!

(victory is sweet )

Of course, sceptics, still adherent to socalled "local realistic models" could still argue that this is not an experiment that closes all loop-holes together but only the fair-sampling assumption.

I think you are way too optimistic:

http://arxiv.org/abs/1212.0533]“Benefiting[/PLAIN] from a wavelength-optimized optical structure, these detectors have been reported to demonstrate detection efficiencies of up to 98%, including losses from packaging and fiber coupling”

True fundamentalists are of course going to claim that a local realistic model is right there in front of our eyes: A lot of “things” can happen in 2%! You just have to believe it!

But taken all experiments together you can say all loop-holes are closed.

Again way too optimistic, I think we just have to accept that there are dogmatic communities that for some weird reason have gotten the right to call the most precise scientific theory in human history – and maybe the greatest human achievement of all – a “Drama Theory” and also have the right to make references to “verbal rebuttals”, where brilliant, rigorous and honorable scientist and proponents of the officially accepted theory are dismissed as the “Quantum Mystery Cult” whom “euphemistically labels their failure as loopholes”, including conspiracy cherry picking obscurely adjusted data “based on metaphysical and unverified (or unverifiable) ad hoc rules”.

I guess we just have to live with (but I sure hope a least some are ashamed today)...

Anyway, I think even if all loop-holes are closed, there's still the possibility open that there might be a non-local realistic model of nature,

But... non-local realistic models are indeed possible even if you accept Bell... or did I miss something? AFAIK these options are left:

• non-local realistic
• local non-realistic (or non-separability)
• non-local non-realistic

(please don’t ask about last ;)

but as long as none is found, we better stick to quantum theory.

Thank you very much vanhees71! This must be the correct way to proceed.

As for Andrey’s work, I’m sure he put a lot of effort in it (including vexatious phrasing* ;) and he should receive credit for this work, even if he lost ‘the battle’. If I’m not mistaken – science is about questioning everything, and maybe most of all; your own arguments (hot tip).

However, reason should normally be a major part of the endeavor. From that perspective, what Andrey has done is brave, or I would say more than brave, because as we know he’s not the first trying to find a Classical Unified Field Theory to replace QM. Schrödinger worked on it for +10 years and Einstein for +20 years (besides a lot of very smart people) and they all failed. And none had to worry about Bell...

What were the odds for Andrey in this light? I say less than ‘nanoscopic’... (with or without Bell)

But maybe the most disastrous fact of all; he was writing his theory on a machine and publishing the result on a communication infrastructure – that would simply not work if QM was wrong.

End of story.


*I’m not innocent in this ‘business’ myself, however I’m just a bum-layman, I don’t write papers, I don’t present new theories, and I convince myself that this saves my little avocado-soul to some extent (but not when it comes to infractions ;), sorry guys

 

[DevilsAvocado]

(Bell wanted to do away with SR and find some aether frame which allows superluminal events)

That doesn’t look right. I watched a lecture Bell held shortly before he died, and he was quite worried about the tension his theorem causes between QM & SR. As I remember, he expressed his thoughts something along these lines:

“If Alice is does the measurement first in one frame of reference, Bob could be first in another frame of reference according to SR, and this doesn’t work... or it’s just me being silly about the whole thing...”

I.e. he was prepared to reduce his work to ‘silliness’ to avoid a conflict with SR.

John Bell was humble man.

 

[akhmeteli]

Of course, sceptics, still adherent to socalled "local realistic models" could still argue that this is not an experiment that closes all loop-holes together but only the fair-sampling assumption. So today, there is not one single experiment that closes all loop-holes at the same time. But taken all experiments together you can say all loop-holes are closed.

We are talking about a theorem, the Bell theorem. Again, we cannot be sure a conclusion of a theorem is valid until all assumptions of the theorem are satisfied, and satisfied simultaneously. I repeatedly gave the following example: "what’s wrong with the following reasoning: planar Euclidian geometry is wrong because it predicts that the sum of angles of any triangle is 180 degrees, whereas experiments demonstrate that the sums of angles of a quadrangle on a plane and a triangle on a sphere are not equal to 180 degrees." The best reply I got was something like: sure, but "it would require a very contrived local theory that would exploit both loopholes in just the right way that it would perfectly agree with QM in all experiments done to date."(https://www.physicsforums.com/showpost.php?p=2814147&postcount=581 ). However, I don't think there is anything contrived about, say, the models of my articles.

 

[DrChinese]

Again, we cannot be sure a conclusion of a theorem is valid until all assumptions of the [Bell] theorem are satisfied, and satisfied simultaneously.

Ah, this is false. The assumptions of the theorem are that there is locality and realism. Given these assumptions, there is incompatibility with the predictions of QM.

What I believe you intend is: the experimental tests to determine whether local realism is ruled out may sometimes rely on the fair sampling assumption, and sometimes rely on the assumption that no signal can propagate from one detector to another (observer dependence). You believe: despite the fact that these have been taken out of the equation one at a time, there may be a physical manner (aka your theory) such that both controlled together will yield a different result. In that case, the cos^2(theta) rule would be shown to be incorrect for entangled particles.

 

[Nugatory]

I repeatedly gave the following example: "what’s wrong with the following reasoning: planar Euclidian geometry is wrong because it predicts that the sum of angles of any triangle is 180 degrees, whereas experiments demonstrate that the sums of angles of a quadrangle on a plane and a triangle on a sphere are not equal to 180 degrees."

This analogy misstates the argument around experimental evidence for Bell's theorem. No one is suggesting that Bell's theorem is false because experiments don't agree with the Bell prediction. Instead, the argument is that because experiment does not agree with the Bell prediction then either:
a) there is an error in the proof of the theorem, such that the conclusion does not follow from the premises; OR
b) the premises do not accurately describe the real world; OR
c) the premises do accurately describe the real world but the experiments do not.

Case #a is a real longshot; Bell's argument has been scrutinized for decades without any error showing up.

Case #b is the one that says that no local hidden variable theory is consistent with the QM predictions. It's the mainstream interpretation of Bell's theorem and the experimental results.

Case #c is the loophole-chaser's argument. It can never be rejected because no experiment is ever free of possible loopholes; we cannot exclude the possibility that a malicious, clever, invisible, and omnipotent fairy is manipulating our lab equipment to produce wrong but internally consistent results.

Whether you choose #b or #c to explain the experimental results is a matter of which one strains your credulity more. #b is getting better all the time, and the #c arguments are looking ever more contrived and implausible... but that doesn't make them provably wrong, just implausible.

 

[audioloop]

I know that this is how realism is often defined in the context of quantum theory. Sometimes this "realism" is called "EPR realism". Actually, I don't believe in such "realism", and I stated that long ago (https://www.physicsforums.com/showpost.php?p=2534347&postcount=34 ): "As I tend to think Einstein was wrong about the uncertainty principle, I am not crying for that particular school." However, the notion of realism exists irrespective of quantum theory and means something different. Santos (http://arxiv.org/abs/quant-ph/0410193 , section II) illustrates this using the example of coin tossing: "head" state or "tail" state does not exist for a coin independently of the measurement procedure, even though the relevant measurement is classical.
.

interesting.

 

[vanhees71]

We are talking about a theorem, the Bell theorem. Again, we cannot be sure a conclusion of a theorem is valid until all assumptions of the theorem are satisfied, and satisfied simultaneously. I repeatedly gave the following example: "what’s wrong with the following reasoning: planar Euclidian geometry is wrong because it predicts that the sum of angles of any triangle is 180 degrees, whereas experiments demonstrate that the sums of angles of a quadrangle on a plane and a triangle on a sphere are not equal to 180 degrees." The best reply I got was something like: sure, but "it would require a very contrived local theory that would exploit both loopholes in just the right way that it would perfectly agree with QM in all experiments done to date."(https://www.physicsforums.com/showpost.php?p=2814147&postcount=581 ). However, I don't think there is anything contrived about, say, the models of my articles.

You have to distinguish between mathematical theorems and physical laws. If you give a sufficiently strict definition of the buzz words "local" and "realistic" you can prove Bell's inequality for probabilities of the outcome of measurements on observables within this mathematical realm named "local realistic theory". This is a true statement within the mathematical world (axiom system) you consider. Then there is another mathematical frame work about probabilities for the outcome of measurements, called quantum theory, where this inequality can be violated and thus quantum mechanics cannot be a "local realistic theory" in the sense of Bell's theorem. That's all what's stated.

So far, all this has nearly nothing to do with physics as a description of the natural world around us. So for this mathematical ideas to become a statement about physics you have to make a connection with real experiments. As discussed in this thread, the experiments done so far, all hint to a violation of Bell's inequality, which is valid for local realistic theories, and a confirmation of the predictions of quantum theory, but there are loop-holes, e.g., the one that each detector (e.g., for photons) has a limited efficiency, i.e., not all photon pairs in a Bell experiment with polarization-entangled photons are registered and one may argue that this spoils the validity of the test. Although that's unlikely to be the case, that the limited efficiency of the photo detectors lead to a violation of Bell's inequality in precisely the way predicted by quantum theory, you cannot totally exclude this possibility, and that's why experimentalists try to these get rid of this and other loop holes. So far everything speaks for quantum mechanics and that either "locality" or "realism" or both have to be abandoned as an assumption about the properties of descriptions of nature.

The same holds true for you example with Euclidean and non-Euclidean geometry. Within Euclidean geometry the theorem that the sum of the angles in a triangle must be 180 degrees is true. That this sum is larger for triangles on a sphere is also true, but a sphere is not a model for Euclidean but for spherical geometry, which explains that the theorem about the angle sum from Euclidean geometry doesn't apply on the sphere. This is a clearly solved statement about different mathematical objects (Euclidean vs. non-Euclidean geometry). It has nothing to do with physics either, when discussed on this level of pure mathematical thoughts.

This is even a much simpler issue than the question, whether Euclidean or non-Euclidean geometry is a better description for physical space. As we know today from precise measurements in the gravitational field of the Earth and observing the motions of planets, stars, and galaxies, according to General Relativity (GR), non-Euclidean geometry gives a better model for space, and it depends on the observer, which geometry is valid for him or her. Fourdimensional space-time, of course, has a well-defined observer-independent pseudo-Riemannian geometry (within GR).

 

[DevilsAvocado]

Case #c is the loophole-chaser's argument. It can never be rejected because no experiment is ever free of possible loopholes; we cannot exclude the possibility that a malicious, clever, invisible, and omnipotent fairy is manipulating our lab equipment to produce wrong but internally consistent results.

[my bolding]

That must be the ultimate “Drama Theory”, right!?

 

[DevilsAvocado]

But taken all experiments together you can say all loop-holes are closed.

The best reply I got was something like: sure, but "it would require a very contrived local theory that would exploit both loopholes in just the right way that it would perfectly agree with QM in all experiments done to date."(https://www.physicsforums.com/showpost.php?p=2814147&postcount=581 ). However, I don't think there is anything contrived about, say, the models of my articles.

While the Bell inequalities cannot be violated in the theories of Ref. [1], there are some reasons to BELIEVE these inequalities cannot be violated either in experiments or in quantum theory: on the one hand, there is no loophole-free experimental evidence of violations of the Bell inequalities (see, e.g., Ref. [2]), on the other hand, to prove that the inequalities can be violated in quantum theory, one needs to use the theory of quantum measurements, e.g., the projection postulate.

First, I agree with opponents of local realistic theories that the Bell inequalities cannot be violated in such theories. However, I don't BELIEVE these inequalities can be violated either in experiments or in quantum theory. First, in spite of anything that was written about experimental demonstration of such violations, there is a consensus among experts that all experiments so far were not free of some loopholes (detection loophole, locality loophole, etc.) Let me quote Abner Shimony and Anton Zeilinger, who are no fans of local realistic theories:

[my bolding & caps]

As you see vanhees71, there aren’t even any “models” regarding Bell, just personal speculations and believing. No math, no experiments, no nothing – just words.

On top of that we have staggering “quotation cherry picking”, to make it look like there are no experimental proofs, and this of course is “confirmed” by ‘Mr. Beam’ himself, Anton Zeilinger. Sigh.

The least one would expect in a scenario like this, is some mathematical support for the astounding rebuttal “these inequalities cannot be violated either in experiments or in quantum theory”, but not a single line from the PhD in theoretical and mathematical physics.

Maybe the most contrived I’ve seen on PF...

 

[DevilsAvocado]

[...] using the example of coin tossing: "head" state or "tail" state does not exist for a coin independently of the measurement procedure, even though the relevant measurement is classical.

interesting.

Interesting indeed, akhmeteli has thrown away superdeterminism, his last hope among the "¡Three Amigos!":

• Realism
• Locality
• Free will

Bell’s theorem stipulates that QM violates at least one of these three assumptions, and now there’s only the first two left...

The most plausible explanation is probably this:

https://www.physicsforums.com/showpost.php?p=2589668&postcount=204

Dear DrChinese,

Thank you very much for your input, and let me explain my position. I am not an expert in the Bell theorem

[my bolding]

...

 

[dlgoff]

The most plausible explanation is probably this:

https://www.physicsforums.com/showpost.php?p=2589668&postcount=204

[my bolding]

...

You Devil

 

[DevilsAvocado]

You Devil

... eh um ... of course this is nothing personal, it’s all about that ‘little’ theorem that seems to cause so much headache for some ... and there’s no doubt that akhmeteli has at least two orders of magnitude greater IQ than me ... and he knows things that I will never understand ... and this is maybe the biggest mystery of all ... how could he not get it?? ... the math is extremely simple, in fact at the kindergarten/avocado level ... classic says 1+1=2 and QM says 1+1=3 ... not much to misinterpret, is it? ... it’s almost sad he invested all this talent and time in a dead end project like this ... and why not be absolutely sure he got it all right from the beginning ... before refuting something he maybe hasn’t grasp all the way ... I don’t get it ... why not accept what we got and instead invest all this human computational power in investigating what it would mean if SR & QM is right and MWI is wrong? ... my guess is that it could be something very interesting around that corner ... maybe ... anyhow my act of avocado contrition if akhmeteli is hurt ... it’s ‘only’ about science, right?

 

[akhmeteli]

Ah, this is false. The assumptions of the theorem are that there is locality and realism. Given these assumptions, there is incompatibility with the predictions of QM..

Actually, there are more assumptions. We assume: 1) locality, 2) realism, 3) free will, 4) spacelike separation of measurements, 5) using certain correlations. Then the Bell theorem says that those correlations satisfy some inequalities. So, to prove violations of the Bell inequalities in an experiment, and thus eliminate local realism with free will, one must make sure ALL assumptions are fulfilled simultaneously. For example, if there is a locality loophole, the spacelike separation does not hold, and the inequalities do not necessarily hold for local realistic theories with free will. If there is a detection loophole, one uses wrong correlations (obtained using the fair sampling assumption), not those of the theorem, so we don't really demonstrate that the true correlations of the Bell theorem are indeed violated, it is the wrong correlations that are violated, so the experiment does not eliminate local realism with free will, and so on.

On the other hand, I do agree that local realism with free will is not compatible with standard quantum theory. I just add that this not a problem of local realism with free will, as standard quantum theory is not compatible with itself as well (as it contains both unitary evolution and the projection postulate.

What I believe you intend is: the experimental tests to determine whether local realism is ruled out may sometimes rely on the fair sampling assumption, and sometimes rely on the assumption that no signal can propagate from one detector to another (observer dependence). You believe: despite the fact that these have been taken out of the equation one at a time, there may be a physical manner (aka your theory) such that both controlled together will yield a different result. In that case, the cos^2(theta) rule would be shown to be incorrect for entangled particles.

So how does this contradict my phrase "we cannot be sure a conclusion of a theorem is valid until all assumptions of the [Bell] theorem are satisfied, and satisfied simultaneously"? If the assumptions are not fulfilled simultaneously, we cannot be sure the inequalities hold for a local realistic theory with free will, so experiments demonstrating violations do not eliminate such theories.

 

[bohm2]

That doesn’t look right. I watched a lecture Bell held shortly before he died, and he was quite worried about the tension his theorem causes between QM & SR...he was prepared to reduce his work to ‘silliness’ to avoid a conflict with SR.

Yes. That seemed to be a major concern for Bell. He writes:

For me then this is the real problem with quantum theory: the apparently essential
conflict between any sharp formulation and fundamental relativity. That is to say, we have an apparent incompatibility, at the deepest level, between the two fundamental pillars of contemporary theory...

Bell, in some papers, seems to argue for a return to Lorentzian view with privileged reference frame as per Bohm but does refer to it as "cheap resolution":

It may well be that a relativistic version of [quantum] theory, while Lorentz invariant and local at the observational level, may be necessarily non-local and with a preferred frame (or aether) at the fundamental level...

I would say that the cheapest resolution is something like going back to relativity as it was before Einstein, when people like Lorentz and Poincare thought that there was an aether-a preferred frame of reference-but that our measuring instruments were distorted by motion in such a way that we could not detect motion through the aether. Now, in that way you can imagine that there is a preferred frame of reference, and in this preferred frame of reference things do go faster than light...

Behind the apparent Lorentz invariance of the phenomena, there is a deeper level which is not Lorentz invariant...[This] pre-Einstein position of Lorentz and Poincare, Larmor and Fitzgerald, was perfectly coherent, and is not inconsistent with relativity theory. The idea that there is an aether, and these Fitzgerald contractions and Larmor dilations occur, and that as a result the instruments do not detect motion through the aether- that is a perfectly coherent point of view.

J.S. Bell’s Concept of Local Causality
http://arxiv.org/pdf/0707.0401.pdf