Is action at a distance possible as envisaged by the EPR Paradox.

[DevilsAvocado]

Yet taking the wavefunction serious as a real physical state provides an EPR mechanism.

But... QM stipulate "no signals"... ??

 

[my_wan]

But... QM stipulate "no signals"... ??

As am I. The mechanism would still be local phenomena, using the local field interactions, while the other detector reacts the same to its local field the same way. I'm just trying to inject QM effects in that local interaction in as realistic a way possible. But the reality atm is that I'm going beyond what I can demonstrate right now, and should back up to the more limited factual elements of the argument.

 

[ThomasT]

DrC, in a recent reply to my-wan you stated:

Otherwise, you will suffer the same fate as ThomasT: I will pick apart your statements because it is wrong for you to use PhysicsForums as a soapbox for personal pet theories.

The fate that I've suffered is that my understanding of the issues involved in determining the meaning of Bell's theorem has increased due to these recent discussions. My thanks to all who contributed to these discussions for that.

As for a pet theory, I don't have one. Any particular modelling attempts have been presented simply to clarify what is and isn't possible given certain assumptions. So, it would be misunderstanding, and mischaracterizing, the aim and the content of my participation in these discussions to say that I was using PF as a "soapbox for personal pet theories", or, as I explain below, to say that my approach to understanding Bell's theorem is nonstandard wrt the traditions of modern science.

I presented one preprint of an LR model, which reproduced the qm predictions, for you to look at and comment on. You didn't do that. Instead you asked for the model to produce a "dataset" which doesn't agree with qm predictions. This confusion is addressed in the following paragraph.

What some people in this, and other recent related, threads are discussing, and what I'm interested in exploring, is the possiblity that the restriction that any (and all) LR models of entanglement be constructed in terms of "local hidden variables" (which has certain implications wrt the form that any such model can take) doesn't apply to a rather wide range of local realistic models which aren't, strictly speaking, local hidden variable models, but are, nonetheless, compatible with the notions of c-limited locality and seperable predetermination. This has to do with the consideration that the parameters involved in the joint measurement context are not themselves "elements of reality" but rather relationships between those elements.

So, I can absolutely agree with this expression of Bell's theorem:

"No physical theory of local Hidden Variables can ever reproduce all of the predictions of Quantum Mechanics."

And, still entertain the possibility that LR models of entanglement are possible.

So, when I say that Bell's logic was flawed, what I mean is that, if his program was to give a general form for any and all LR models, then, imo, he didn't do that. On the other hand, if his program was to give a general form for any and all LHV models, then, imo, he did that. And since I think his program was the former, and that his analysis didn't take into account the contextual parameters (not LHV's) which determine joint detection (but not individual detection), then the application of his ansatz to entanglement preparations was logically flawed. The same reasoning applies to GHZ, Hardy, and any other theorems which rule out LHV, but not all LR, models of entanglement.

We know for sure that Bell's formulation is incompatible with qm and experimental results. The fact that it's incompatible with experimental results demonstrates that it incorrectly models the experimental situations to which it's being applied. From this, some people (1) choose to trash a pillar (or two?) of modern science, while other's (2) choose to look more closely at Bell's construction to explore the possibility that maybe it has no corollaries pertaining to what does or doesn't exist in nature. I would characterize (1) as somewhat nonstandard wrt accepted methods of scientific inquiry, because (2) is ongoing.

Referring to the preceding quoted expression of Bell's theorem, you ask:

You think that this shows a physical meaning which is more general than justified empirically?

No, I agree with you that it doesn't.. And as long as Bell's theorem is expressed that way then it's clear enough that it doesn't imply anything about nature.

And you continue with:

I don't see this as something which is empirical. Nor do I see it as more general than warranted. Nor am I aware of any physical theory which threatens this conclusion.

Again, I agree with you on this. We seem to agree that Bell's theorem doesn't provide a basis for assuming nonlocality or ftl. But since you seem to want to hold onto the idea that nonlocality is, in some sense, possible, then I'll grant you that, in the sense that none of us has any unassailable ideas regarding the reality underlying our sensory experience so that pretty much 'anything' is possible wrt deep reality, then, in that sense, nonlocality is possible. Just that, without Bell's theorem as a basis, it isn't a reasonable assumption (ie., it doesn't follow from what's known).

 

[DrChinese]

DrC, in a recent reply to my-wan you stated:...

Hey, I hope you know I am glad you are here. I hope nothing I say discourages you in any way. In fact, I encourage you to challenge from every angle. I enjoy a lot of your ideas and they keep me on my toes.

I think you know that there are a lot of readers who are not active posters in many of our discussions. Just look at the view count on these threads. While I know what is what throughout the thread, these readers may not. That is why I frequently add comments to the effect of "not generally accepted", "show peer reviewed reference" , etc. my_wan and billschnieder get that too. So my objective is to keep casual readers informed so that they can learn both the "standard" (generally accepted) and the "non-standard" (minority) views. I would encourage any reader to listen and learn to a broad spectrum of ideas, but obviously the mainstream should be where we start. And that is what PhysicsForums follows as policy as well.

On the other, when posters suitably label items then that is not an issue and I don't feel compelled to add my (sometimes snippy) comments. Also, many times a personal opinion can be converted to a question so as not to express an opinion that can be mistrued. For example: "Is it possible that Bell might not have considered the possibility of X?". That statement - er question - does not attempt to contradict Bell per se. And then the discussion can continue.

And less feelings get hurt. And people won't think I am resorting to authority as a substitute for a more convincing argument. As I often say, it only takes one. Of course, me being me, that line is stolen (in mangled form) from a man who is quite well known. In fact, maybe it is time to add something new to my tag line...

 

[DevilsAvocado]

... As I often say, it only takes one.

Good post DrC, and to the "readers" we maybe should explain the "stolen line", which is both brilliant and humorous.

Leipzig, Germany in early 1931 (propaganda), a booklet that denied the theories of Albert Einstein was titled:
"One Hundred Scientists against Einstein"

Einstein -- "Why 100? If I were wrong, then one would have been enough!"

 

[DrChinese]

Good post DrC, and to the "readers" we maybe should explain the "stolen line", which is both brilliant and humorous.

Leipzig, Germany in early 1931 (propaganda), a booklet that denied the theories of Albert Einstein was titled:
"One Hundred Scientists against Einstein"

Einstein -- "Why 100? If I were wrong, then one would have been enough!"

Suitably modified.

Einstein had so many great quotes, in addition to his marvelous contributions to science.

 

[my_wan]

As for a pet theory, I don't have one. Any particular modelling attempts have been presented simply to clarify what is and isn't possible given certain assumptions. So, it would be misunderstanding, and mischaracterizing, the aim and the content of my participation in these discussions to say that I was using PF as a "soapbox for personal pet theories", or, as I explain below, to say that my approach to understanding Bell's theorem is nonstandard wrt the traditions of modern science.

My own realist slant is based on the fact that the default and presumably the most defensible position is against it, and I made no bones about the precariousness of my arguments. BI violations are often billed as proof of either non-local or non-realism. To maintain that requires standing up to even "in principle" mechanisms. To that a class of lhv's exist that in principle that does that, but mostly involve contentious issues with fundamental principles and definitions of realism. So I object to an unequivocated proof claim, while I'm perfectly content with the default position being a general acceptance of BI. It is this acceptance on which the search for falsification is predicated, just as it should be.

Yes, outside readers should understand that the default position is and should be an acceptance of BI. Science also gains it's strength through standing up to falsification, so countering the default position is part of the process. Implying that attempts at falsification is not science, but prejudice, doesn't serve science well. So long as those countering are not demanding their position as absolute truth.

 

[DrChinese]

Yes, outside readers should understand that the default position is and should be an acceptance of BI. Science also gains it's strength through standing up to falsification, so countering the default position is part of the process.

Thanks for clarifying that. It really helps if you mention that from time to time, so the other readers don't accidentally get the wrong impression. Someone who starts reading in the middle of the thread (which is most) will benefit greatly from knowing the sides as they listen and learn.

Keep in mind that persuading you to change your position is not really my objective. If that happens, fine, but there are lots of people who have the same questions or concerns as you. You deserve the best anyone here can offer. If anything I say helps you to frame your position better, then I am happy.

 

[my_wan]

What I want doesn't involve a position to be changed, as I accepted my position for debate purposes was precarious from the beginning. I want a clearer view of how to model the situation with or without realism, and I feel that pitting BI violations against potential realistic models helps, valid or not. As is well known, BI is not directly related to QM but far more general. It seems fairly obvious that any explanation must involve mechanisms consistent with QM, realistic or not. Articulating precisely if and how realistic models fall short leads to clues about precisely what QM principle are involved.

This is why the debate is leading me toward the Born rule, and the general lack of rotational invariance in vectorial products. Vector products of the type the Born rule imposes is generally avoided in physics for this reason. The squaring to get observable magnitudes would also provide for the nonlinearity in the detection counts at various offsets. So a realism argument might ultimately come down to a realistic mechanism for the Born rule. Even lacking this, if it can be demonstrated that the Born rule alone can provide the mechanism, it would be quiet significant.

I will continue to object to BI violations being presented as an overly general "proof", however significant and physically valid experimentally. I object almost as strongly as I would to absolute claims that it must have a realistic explanation.

 

[DevilsAvocado]

Suitably modified.

P l e a s e tell me you changed your signature just now!? ...or I have to get new glasses...


EDIT: Just realized what happened here. I was reading your post without being logged in, and then your signature doesn’t show (why? ). For those readers who aren’t registered users, my comment could be 'useful' after all... (and I can keep my old glasses )

 

[DevilsAvocado]

DrChinese & my_wan

How about a request to PF Admin for a new option in PF that would allow us to set a "Footer Disclaimer" (maybe thread specific), that is shown whether the "readers" are logged on or not?

This would probably avoid a lot of unnecessary internal "hubbub"... and be a guarantee for the reader not to get the wrong "impression"...

My "Disclaimer" would look something like this:

I’m a 100% curious layman looking for more knowledge. Naturally, I accept all standards in the scientific community, but I think it’s fun to find (what I imagine) new perspectives and questions (that probably already have been answered). Everything I say can be totally wrong (read at own risk), though I regard myself as perfectly sane - but even this fact could be questioned by some. ​

(Realize... this would only work as a "popup function"...)

What do you think?

 

[DevilsAvocado]

EPR-Bell Experiment for Dummies
A Reference for the Rest of Us

Found a very informative video which explains all parts in a modern EPR-Bell setup.

https://www.youtube.com/watch?v=<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/c8J0SNAOXBg&hl=en_US&fs=1&rel=0&color1=0x006699&color2=0x54abd6"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/c8J0SNAOXBg&hl=en_US&fs=1&rel=0&color1=0x006699&color2=0x54abd6" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>

 

[DrChinese]

I will continue to object to BI violations being presented as an overly general "proof", however significant and physically valid experimentally. I object almost as strongly as I would to absolute claims that it must have a realistic explanation.

my_wan, I honestly think you are stretching the meaning of the words a bit (and I am not trying to criticize as I see words to the same effect from others too). Absolute might be a little strong about ANYTHING we think we know. At some point, you have to say: this is proven, this is supported experimentally, or this is a conjecture. Clearly, all sides are NOT equal.

I would say that Bell is proven, local realism is not experimentally supported, and there are conjectures regarding various interpretations. Are any of these absolutes? I think each of us has a slightly different opinion on that and I don't think that is too important. But it would be quite unfair to characterize local realism as being on the same footing as QM in terms of Bell/Bell tests.

 

[my_wan]

Absolute may be too strong, but when it's said Bell's theorem proves non-locality or non-realism, it is overstated. What has been proven is that nature violates BI. I even go with the extension that it has been irrevocably proven is that nature does not assign properties to things in a manner consistent with that one definition of realism.

By the time I was 10 years old, based on purely mechanistic reasoning, the notion of "physical property" as used in classical physics wrt -fundamental- parts, sounded like an oxymoron to me. When I apply that same reasoning today wrt BI, BI violations only justify my original, age 10, issues with the notion of fundamental properties. Yet to insist that experimental evidence that "fundamental property" wrt to things is an oxymoron proves the lack of realism in things requires assuming the definition wasn't an oxymoron from the start. Before I ever even started kindergarten, I was sneaking rocks in the car to drop out the window, to compare how the path looked from inside and outside the car. I tried using telephone poles and mail boxes as reference points.

At some point, you have to say: this is proven, this is supported experimentally, or this is a conjecture. Clearly, all sides are NOT equal.

BI violations are proven beyond ANY reasonable doubt. But no, you can't assume that because the fact of BI violations remain factual proves an interpretation of what it means physically.

I would say that Bell is proven, local realism is not experimentally supported, and there are conjectures regarding various interpretations.

Yes, BI violations are factual, and will never go away simply as a result of better experiments. As to what it means wrt realism requires the assumptions that the definition of realism used wasn't predicated on an oxymoron from the start.

If you take a rabbit to have the property 'rabbit, which eats clover with the property 'clover', what happened to the 'clover' property when the rabbit eats it? Does that mean the 'rabbit' property is not 'real'? If no, does that mean the 'rabbit' is not real?

So yes you can say with certainty that BI is valid. You cannot make claims of what it means wrt to realism in general, irrespective of chosen definitions which might even be an oxymoron from the perspective of realism itself, and then claim that the fact that it has remained an oxymoron as defined for some time strengthens the claim realism is falsified. I find it ironic that experimental evidence that my perception at 10, predicated on realism, that 'physical properties' as defined was an oxymoron, is now used to claim realism is falsified.

 

[my_wan]

How did the original EPR paper actually define realism?
http://www.drchinese.com/David/EPR.pdf

This was the primary completeness condition (unequivocated) which is predicated on realism:

Whatever[/PLAIN] the meaning assigned to the term complete, the following requirement for a complete theory seems to be a necessary one: every element of physical reality must have a counterpart in physical theory. We shall call this the condition of completeness.

Now this is far more general than the definition actually used, where it was stated:

A[/PLAIN] comprehensive definition is, however, unnecessary for our purposes. We shall be satisfied with the following criterion, which we regard as reasonable.

Notice the equivocations? The following definition was even, in the original paper, disavowed as a complete specification of realism. The following definition was purely utilitarian for purposes of the argument:

If,[/PLAIN] without in any way disturbing the system, we can predict with certainty (i.e., with probability equal to one) the value of a physical quantity, then there exist an element of physical reality corresponding to this physical quantity.

Note that "there exist an element of physical reality" is not even a condition that the "physical quantity" associated with it must be singular or innate to singular "elements". This was in a sense the basis on which Einstein rejected Neumann's proof. Deterministic (classical) was taken to mean dispersion free, in which the measurables were taken as distinct preexisting properties of individual "beables". Bell showed that the properties of any such "beables" must also depend on the context of the measurement, much like classical momentum is context dependent. How many different times, not counting the abstract, was this definition equivocated? Let's see:
1) A comprehensive definition is, however, unnecessary for our purposes.
2) It seems to us that this criterion, while far from exhausting all possible ways of recognizing a physical reality, at least provides us with one such way, whenever the conditions set down in it occur.
3) Regarded not as necessary, but merely as sufficient, condition of reality, this criterion is in agreement with classical as well as quantum-mechanical ides of reality.

The point here is that not even the original EPR paper supported the notion that an invalidation of the singular utilitarian definition used was itself an invalidation of reality, or that singular properties represented singular elements. It allowed many more methods and contexts with which to define reality, and merely chose this one to show, given the assumptions, that cases existed where conservation law allowed values lacking a real values in QM could be predicted when QM defined them as fundamentally undefined. To predicate a proof on this singular utilitarian definition as proof that all definitions of objective reality are falsified goes well beyond the claims of the EPR paper. It is also this artificial restriction, to this utilitarian definition provided, that is the weakness in the proof itself.

Look at the rabbit analogy again. Given a rabbit and its diet, the physical quantity of a substance with the property [rabbit poo] is predictable. That by definition, under the utilitarian definition used, defines [rabbit poo] as an element of reality, but does that means the rabbit poo property is also an element of reality. If so, where was the "poo" property before the rabbit eat the clover? If not does mean the "poo" property does not define an element of reality? The only reasonable assumptions are:
1) The [rabbit poo] property in fact represents an element of reality.
2) The [rabbit poo] property is not itself a physical element of reality, but a contextual element of reality representing a real physical state.
3) The rabbit poo itself is a physical element of reality.

Taken this way, BI violations might only indicate that ALL measurable properties have the same contextual dependence as every property we are familiar with in the everyday world. It may only be our notion that fundamental properties of "beables" exist that is at fault. Yet a "beable" lacking measurable properties of its own may still gain properties through persistent, or quasi-persistent, interactions with other beables. A Schneider quote I like a lot from "[URL Determinism Refuted[/URL], illustrating the unobservability of independent variables is fitting here. This entails that what we perceive as the physical world is built from verbs, rather than nouns, but doesn't prove that nouns don't exist to define the verbs. So the claim of a proof of the nonexistence of beables goes well beyond any reasonable level of generality that can be claimed.

The issue of completeness is twofold. If -every- possible empirical observation and prediction is contained within a mathematical formalism, is it complete? I would say so, even if reality contains physical constructs at some level, not defined in the formalism, that provides for the outcomes predicted by the formalism. Einstein insisted on these physical constructs being specified in order to qualify as complete. Funny he didn't insist on the same with his own theories, presumably on the grounds that they didn't conflict with certain realist notions. Thus I don't consider, as Einstein did, that every element of physical reality must have a counterpart in physical theory to be considered complete. If QM is considered lacking in completeness, gravity is the issue. Yet a model, complete in the Einstein sense, would be a useful construct, and maybe even play a pivotal role in unification.

 

[DevilsAvocado]

... but does that means the rabbit poo property is also an element of reality.

If the rabbit poo hits the fan, then I think most would regard 3) as the most plausible alternative.

Seriously, I’m not quite following all this talk about what is real or not... is a measured photon more real than an unmeasured photon?? Is the measuring apparatus 100% real??

According to Quantum Chromodynamics (QCD) both rabbit poo and measuring apparatus consist of 90% virtual particles, popping in and out all the time:

[URL]http://www.physics.adelaide.edu.au/~dleinweb/VisualQCD/QCDvacuum/su3b600s24t36cool30actionHalf.gif[/URL]

So, what is really real real or counterfactual real or context real, etc !?!?

 

[DrChinese]

How did the original EPR paper actually define realism?
http://www.drchinese.com/David/EPR.pdf

This was the primary completeness condition (unequivocated) which is predicated on realism:

Now this is far more general than the definition actually used, where it was stated:

Notice the equivocations? The following definition was even, in the original paper, disavowed as a complete specification of realism. The following definition was purely utilitarian for purposes of the argument:

Note that "there exist an element of physical reality" is not even a condition that the "physical quantity" associated with it must be singular or innate to singular "elements". This was in a sense the basis on which Einstein rejected Neumann's proof. Deterministic (classical) was taken to mean dispersion free, in which the measurables were taken as distinct preexisting properties of individual "beables". Bell showed that the properties of any such "beables" must also depend on the context of the measurement, much like classical momentum is context dependent. How many different times, not counting the abstract, was this definition equivocated? Let's see:
1) A comprehensive definition is, however, unnecessary for our purposes.
2) It seems to us that this criterion, while far from exhausting all possible ways of recognizing a physical reality, at least provides us with one such way, whenever the conditions set down in it occur.
3) Regarded not as necessary, but merely as sufficient, condition of reality, this criterion is in agreement with classical as well as quantum-mechanical ides of reality.

The point here is that not even the original EPR paper supported the notion that an invalidation of the singular utilitarian definition used was itself an invalidation of reality, or that singular properties represented singular elements. It allowed many more methods and contexts with which to define reality, and merely chose this one to show, given the assumptions, that cases existed where conservation law allowed values lacking a real values in QM could be predicted when QM defined them as fundamentally undefined. To predicate a proof on this singular utilitarian definition as proof that all definitions of objective reality are falsified goes well beyond the claims of the EPR paper. It is also this artificial restriction, to this utilitarian definition provided, that is the weakness in the proof itself.

I do agree with much of what you are saying here. There are definitely utilitarian elements to Bell's approach. But I may interpret this in a slightly different way than you do. In my mind, Bell says to the effect: "Define realism however you like, and I would still expect you to arrive at the same place." I think he took it for granted that the reader might object to any particular definition as somewhat too lenient or alternately too restrictive. But that one's substitution of a different definition would do little to alter the outcome.

Again, for those following the discussion, I would state as follows: EPR defined elements of reality as being able to predict the result of an experiment without first disturbing the particle. They believed that there were elements of reality for simultaneous measurement settings a and b. Bell hypothesized that there should, by the EPR definition, be also a simultaneous c. This does not exist as part of the QM formalism, and is generally disavowed as part of most treatments. So it is a requirement of the realistic school, i.e. the school of thought that says that hidden variables exist. But not an element of QM.

 

[DrChinese]

Look at the rabbit analogy again. Given a rabbit and its diet, the physical quantity of a substance with the property [rabbit poo] is predictable. That by definition, under the utilitarian definition used, defines [rabbit poo] as an element of reality, but does that means the rabbit poo property is also an element of reality. If so, where was the "poo" property before the rabbit eat the clover? If not does mean the "poo" property does not define an element of reality? The only reasonable assumptions are:
1) The [rabbit poo] property in fact represents an element of reality.
2) The [rabbit poo] property is not itself a physical element of reality, but a contextual element of reality representing a real physical state.
3) The rabbit poo itself is a physical element of reality.

The EPR view was that there was an element of reality associated with the ability to predict an outcome with certainty. There was no claim the what was measured was itself "real", as it was understood that it might be a composite or derived quantity. Is temperature real?

But the EPR view was also that the element of reality is non-contextual. They said that any other view was "unreasonable".

 

[DevilsAvocado]

(my_wan, sorry for the silly rabbit joke... parrots & rabbits + EPR seems to short circuit my brain...)


I’m going to stick my layman nose out, for any to flatten.

To my understanding, Einstein didn’t like the idea that nature was uncertain according to QM. That was the main problem – not if A & B was "real" or not.

Einstein formulated the EPR paradox to show that there was a possibility to get 'complete' information about a QM particle, like momentum and position, by measuring one of the properties on a twin particle, without disturbing the 'original'.

One cornerstone in QM is the Heisenberg uncertainty principle, which says it’s impossible to get 'complete' information about a QM particle (like momentum and position), not because the lack of proper equipment – but because uncertainty and randomness is a fundamental part of nature.

Einstein raised the bet and placed his own special theory of relativity at stake (probably certain it couldn’t fail) stating – either local hidden variables exist, or spooky action at a distance is a requirement – to explain what happens in the EPR paradox.

Einstein didn’t know that his own argument would boomerang back on him...

And here we are today with a theoretical proven and physical (99,98%) theory stating that the QM world is non-local, in Bell’s theorem.

This means, beyond any doubt, that GR <> QM and to solve this dilemma we need to get GR = QM.

So gentlemen, why all this 'fuss' about reality, counterfactuals, context, C, etc?

 

[my_wan]

The EPR view was that there was an element of reality associated with the ability to predict an outcome with certainty. There was no claim the what was measured was itself "real", as it was understood that it might be a composite or derived quantity. Is temperature real?

Yes, exactly. But the issue is what BI has to assume about the contextually of the measured values wrt elements of reality. EPR needed only the fact it was predictable, and no other assumption. I have to object to your next claim.

But the EPR view was also that the element of reality is non-contextual. They said that any other view was "unreasonable".

No. EPR did not assume reality is non-contextual. The "unreasonable" quote only denied a singular form of contextuality, i.e., that the reality of measurement P was dependent on measurement Q. That is certainly far from the only form of contextuality that exist, and the interpretation the BI demonstrates this form denies any other form of contextuality, and presumes correlation equals causation. It would certainly be "unreasonable" to conclude that classical physics does not allow correlations without the defining the measurement itself as the causative agent of the correlation.

Consider what it entails if we assume a realist perspective of BI violations.
1) Correlations at common detector settings is a physical certainty.
2) Offsets from a common detector setting introduces noise, completely random from an experimental/empirical perspective.

Now, via BI violations, counterfactually we can show the randomness of the noise in 2) cannot show the same randomness wrt another detector setting. Well big shocker when arbitrary but common detector settings doesn't show any significant randomness. If this noise itself is -fundamentally- deterministic but unpredictable, then you can always choose an after the fact measurement you could have done that would have given a different value than the expectation value of this randomness. The same for any random series of predefined heads/tails can be chosen after the fact to show a non-random correlation with a set of coin tosses.

To illustrate, note how in the negative probability proof the non-correlations, (Y = SIN^2(45 degrees), are given the same ontological certainty status as the correlations at common angles. Certainly, from a purely statistical standpoint, the noise of 2) is a certainty in the limit. Yet if you assume a realist position, you can always choose an after the fact condition in which noise becomes a signal, or visa versa. I can win the lottery every time if I can choose after the fact.

Of course, a good rebuttal is, the problem in BI violations is that BI violations are always inconsistent with what an alternative measurement would have indicated. The problem here is that the randomness of the noise in 2) is given the same ontological status as the certainty of 1). When you define a counterfactual channel, you are by definition imposing a non-random after the fact condition on C. The noise of the counterfactual channel is predefined to be non-random wrt any performable actual experiment, for either leg A or B, since it is after the fact correlated and anti-correlated respectively. This entails that the noise is -predefined- to be inversly related to the randomness of any actual measurement of A and B, thus the randomness of Y = SIN^2(45 degrees) is defined out of it after the fact. Like calling heads after the toss. The stochastic noise can't be considered to have the same ontological certainty status as the certainty of the physical correlation itself, which exist even when the noise introduced by offsets shows noncorrelated measurements.

I still think the Born rule is probably directly involved here, which by itself would give realist a headache. I haven't had time to test my rotationally variant vectorial ideas yet either. I'll get to it sooner or later.

 

[my_wan]

This means, beyond any doubt, that GR <> QM and to solve this dilemma we need to get GR = QM.

So gentlemen, why all this 'fuss' about reality, counterfactuals, context, C, etc?

Because precisely what we can presume about reality, counterfactuals, context, etc., plays a large role in what we can consider to get GR <> QM to GR = QM. Short of doing that, I don't see the value of purely interpretive models.

And your rabbit poo joke was fine

 

[ThomasT]

I still think the Born rule is probably directly involved here, which by itself would give realist a headache.

Why do you think that? Doesn't the Born rule have an empirical basis?

 

[ThomasT]

But the EPR view was also that the element of reality is non-contextual. They said that any other view was "unreasonable".

The EPR view was that the element of reality at B determined by a measurement at A wasn't reasonably explained by spooky action at a distance -- but rather that it was reasonably explained by deductive logic, given the applicable conservation laws.

That is, given a situation in which two disturbances are emitted via a common source and subsequently measured, or a situation in which two disturbances interact and are subsequently measured, then the subsequent measurement of one will allow deductions regarding certain motional properties of the other.

Do you doubt that this is the view of virtually all physicists?

Do you see anything wrong with this view?

 

[zonde]

Let's get inequality violations without correlation in a single PBS:
Let's assume a perfect detection efficiency in a single channel, 100% of all particles sent in this channel get detected either go left or right using a PBS. Consider a set of detections at this PBS at angle 0. 50% go left and 50% right. Now if you ask which left would have went right, and visa versa, these photons would have went at an angle setting of 22.5, it's reasonable to say ~15% that would have went left go right, and visa versa.

This is only true if the source produces only H and V photons.
You can easily check it with such setup. Let's say single run of experiment lasts 10 seconds. Our photon source produces H polarized photons for first 5 seconds of experiment and V polarized photons for other 5 seconds.
Say for first 5 seconds all photons appear in PBS channel #1 and for other 5 seconds all photons appear in channel #2. When we rotate PBS by 22.5° we have:
85% photons in channel #1 and 15% photons in #2 for first half and
15% photons in channel #1 and 85% photons in #2 for second half.
So it is indeed reasonable to assume that 15% of photons changed their channel.

However if source produces +45° and -45° polarized photons we will have different picture.
For PBS at 0° we have:
50% photons in channel #1 and 50% photons in #2 for first half and
50% photons in channel #1 and 50% photons in #2 for second half.
For PBS at 22.5° we have:
85% photons in channel #1 and 15% photons in #2 for first half and
15% photons in channel #1 and 85% photons in #2 for second half.
So it is reasonable to assume that 35% of photons changed their channel.

Yet this same assumption indicates that at an angle of 45, ~50% that would have gone left go right (relative to the 0 angle), and visa versa. Yet, relative to angle 22.5, the 45 angle can only have switched ~15% of the photon detection rates. 15% + 15% = 30%, not 50%.

Above explanation indicate that you don't get the problem you are stating here.

 

[zonde]

GHZ tests are not considered to rely on the Fair Sampling assumption.

In original GHZ paper "Bell's theorem without inequalities" (it is pay per view unfortunately) it is said:
"The second step is to show the test could be done even with low-efficiency detectors, provided that we make a plausible auxiliary assumption, which we call fair sampling. Finally, we show that the auxiliary assumption is dispensable if detector efficiencies exceed 90.8%."

Now there is a kicker on this that may confuse folks. It is true that only a sample is used, so you might think the Fair Sampling issue is present. But it is not. The sample looks like this:

-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1...

Where local realism predicts

1
1
1
1
1
1
1
1
1
1
1...

A little consideration will tell you that local realism is falsified in this case. Every case, individually, is a falsification.

GHZ experiments use four photons not one photon.
If we talk about three photon GHZ then it's results are acquired using four different modifications of setup. And GHZ inequalities are calculated from all four results together that each consists of three-fold coincidences in four detectors.
Nothing of this indicates that you can simplify experimental outcome the way you did.

 

[my_wan]

Let's get inequality violations without correlation in a single PBS:
Let's assume a perfect detection efficiency in a single channel, 100% of all particles sent in this channel get detected either go left or right using a PBS. Consider a set of detections at this PBS at angle 0. 50% go left and 50% right. Now if you ask which left would have went right, and visa versa, these photons would have went at an angle setting of 22.5, it's reasonable to say ~15% that would have went left go right, and visa versa.

This is only true if the source produces only H and V photons.

Absolutely not. The statistics, as stated, are in fact predicated on completely randomized polarizations coming from the source. However, if the photons coming from the source were 50% H and V, strictly at those 2 polizations, it would have the same statistical effect, because the rate photons switch paths from H is the same rate they would switch from V in reverse.

But the fact remains, purely randomed polarization would have the same statistics. I went to great lengths to verify this assumption.

You can easily check it with such setup. Let's say single run of experiment lasts 10 seconds. Our photon source produces H polarized photons for first 5 seconds of experiment and V polarized photons for other 5 seconds.
Say for first 5 seconds all photons appear in PBS channel #1 and for other 5 seconds all photons appear in channel #2. When we rotate PBS by 22.5° we have:
85% photons in channel #1 and 15% photons in #2 for first half and
15% photons in channel #1 and 85% photons in #2 for second half.
So it is indeed reasonable to assume that 15% of photons changed their channel.

Yep, but this is quiet different from random polarizations, where any setting of the PBS sends 50% in each direction, but also incidentally matches, at all PBS settings, the statistics as two pure polarizations at 90 degree offsets.

Consider this: Add the first and second set of 5 second runs together and the 85% and 15% wash out, just like what you initially specified above. Now check and see that the same thing happens at all settings. Thus if it always washed out at all settings in the strict H and V cases, why would a completely randomized source, which only changes those same settings via the photons rather than polarizer settings lead to anything different in the overall statistics?

However if source produces +45° and -45° polarized photons we will have different picture.
For PBS at 0° we have:
50% photons in channel #1 and 50% photons in #2 for first half and
50% photons in channel #1 and 50% photons in #2 for second half.
For PBS at 22.5° we have:
85% photons in channel #1 and 15% photons in #2 for first half and
15% photons in channel #1 and 85% photons in #2 for second half.
So it is reasonable to assume that 35% of photons changed their channel.

Yep, but only if the photon from the source are not randomized, which you falsely assumed my description didn't do, simply because the overall statistics happen to match for both pure H and V and randomized photon polarization cases.[/QUOTE]

Yet this same assumption indicates that at an angle of 45, ~50% that would have gone left go right (relative to the 0 angle), and visa versa. Yet, relative to angle 22.5, the 45 angle can only have switched ~15% of the photon detection rates. 15% + 15% = 30%, not 50%.

Above explanation indicate that you don't get the problem you are stating here.

The only mistake I see in your reasoning is thinking that because there is a statistical match between the pure H and V case, and the randomized case, I must have only have been referring the pure H and V case. This is wrong. Check the same statistics for the randomized case and you'll see a statistical match for both cases, but the randomized case would invalidate your +45° and -45° case, because I was assuming the randomized case.

 

[ThomasT]

Hey, I hope you know I am glad you are here.

Was there something in my prior post in this thread that indicated that I think that you're not glad that I'm here? (Please don't misunderstand the 'tone' of any of my posts. A day without you at PF would be like a day without ... sunshine. However, while I do like the fact that the sun is shining, it doesn't contradict the fact of shade. This is just elementary optics which both you and Bell seem to be avoiding in your interpretations of Bell's theorem.)

I quote you from a previous post:

You shouldn't be able to have this level of correlation if locality and realism apply.

This betrays an apparent lack of understanding of elementary optics. Which, by the way, also applies in qm.

I hope nothing I say discourages you in any way. In fact, I encourage you to challenge from every angle. I enjoy a lot of your ideas and they keep me on my toes.

Then, when I, or someone else, offers a, purported, LR model of entanglement that reproduces the qm predictions, why not look at it closely and express exactly why you think it is or isn't an LR model of entanglement?

I think you know that there are a lot of readers who are not active posters in many of our discussions. Just look at the view count on these threads. While I know what is what throughout the thread, these readers may not. That is why I frequently add comments to the effect of "not generally accepted", "show peer reviewed reference" , etc. my_wan and billschnieder get that too. So my objective is to keep casual readers informed so that they can learn both the "standard" (generally accepted) and the "non-standard" (minority) views. I would encourage any reader to listen and learn to a broad spectrum of ideas, but obviously the mainstream should be where we start. And that is what PhysicsForums follows as policy as well.

My approach to understanding Bell's theorem isn't a 'nonstandard' or 'minority' approach. To characterize it as such does a disservice to me and misinforms less sophisticated posters. What you are stating, sometimes, as the mainstream view is, I think, incorrect, and also not the mainstream view.

There's a very important difference between:
1. No physical theory of local Hidden Variables can ever reproduce all of the predictions of Quantum Mechanics.
and:
2. No Local Realistic physical theory can ever reproduce all of the predictions of Quantum Mechanics.

We KNOW that 2. is incorrect, because viable LR models of entanglement exist, and they remain unrefuted. If you refuse to acknowledge them, then so what. They exist nonetheless.

I want readers of this thread to understand this. There are LR theories of entanglement which reproduce all of the predictions of qm. They're in the preprint archives at arxiv.org, and there are some that have even been published in peer reviewed journals. Period. If you, DrChinese, want to dispute this, then it's incumbent on you, or anyone who disputes these claims, to analyze the theories in question and refute their claims regarding locality or realism or compatibility with qm. If this isn't done, then the claims stand unrefuted. And, since no such refutations exist, then the current status of LR theories which reproduce all qm predictions is that they remain unrefuted.

If you don't want to inform casual readers of this thread of this fact, then fine. I've informed them.

And just so there's no confusion about this, let me say it again. Bell's theorem does not rule out local realistic theories of entanglement. If DrChinese disagrees with this, then I want you, the casual reader of this thread, to demand that DrChinese analyze a purported LR theory and show that it either isn't local or realistic or both or that it doesn't reproduce qm predictions.

On the other, when posters suitably label items then that is not an issue and I don't feel compelled to add my (sometimes snippy) comments. Also, many times a personal opinion can be converted to a question so as not to express an opinion that can be mistrued. For example: "Is it possible that Bell might not have considered the possibility of X?". That statement - er question - does not attempt to contradict Bell per se. And then the discussion can continue.

And what you often don't do in many of your statements is to qualify exactly what you're saying. So, bottom line, your statements often perpetuate the myth that Bell's theorem informs us about facts of nature -- rather than facts of what sorts of theoretical forms are compatible with certain experimental situations.

And less feelings get hurt. And people won't think I am resorting to authority as a substitute for a more convincing argument. As I often say, it only takes one. Of course, me being me, that line is stolen (in mangled form) from a man who is quite well known. In fact, maybe it is time to add something new to my tag line...

There are, at least, a dozen different LR models of entanglement in the literature which reproduce the qm predictions. Of course, if you won't look at any of them then 10^1000 wouldn't be enough. Would it?

All you have to do is look at one. If you think it doesn't qualify as a local or a realistic model, then you can point out why (but don't require that it produce incorrect predictions, because that's just silly). If you're unwilling to do that, then your Einstein quote is just fluffy fuzziness wrt your position on LR models of entanglement.

I want you to refute an LR theory of entanglement that I present. You've been called out. Will you accept the challenge?

By the way, I like the Korzybski quote.

www.DrChinese.com "The map is not the territory." - Korzybski.

"Why 100? If I were wrong, one would have been enough." - Albert Einstein, when told of publication of the book One Hundred Authors Against Einstein.

 

[my_wan]

ThomasT has a point wrt mainstream view on the realism issue. I know very few that take as hard a view on realism as DrC. Rather an acceptance the uncertainty in any particular interpretation. Of course my personal experience is limited. However, a review of published opinions is not necessarily indicative of the general opinion. Like the myth that violence is increasing, when in fact it's been steadily dropping year to year for many generations. I would be curious what the actual numbers look like.

So even though BI might specify the status quo of the argument, it's likely much more suspect to claim the standard interpretation represents the predominate view.

The sample looks like this:

-1
-1
-1
-1...

Where local realism predicts

1
1
1
1...

A little consideration will tell you that local realism is falsified in this case.

Only with a very restricted notion of realism and what it entails can this be said. I also never got a response to my objection to calling realistic ways a defining contextualization of such variables a Fair Sampling argument.

I would love to hear a definition of contextual variables? Certain statements made it sound like contextual variables, by definition, meant non-realistic. I never got a response to the questions, is velocity a contextual variable?

I also never got an objection when I pointed out that straight forward squaring of any vector leads to values that are unavoidably coordinate dependent, that is it produces different answers and not just the same answer defined by a different coordinate system. Yet the requirement that a realistic model must model arbitrary detector settings, rather than arbitrary offsets, requires a coordinate independent square of a vector.

To say realism is falsified most certainly is an overreach of what can be ascertained from the facts. I don't care who is right, I want a clearer picture of the mechanism, locally realistic or not.

 

[DevilsAvocado]

I must inform the casual reader: Don’t believe everything you read at PF, especially if the poster defines you as "less sophisticated".

Everything is very simple: If you have one peer reviewed theory (without references or link) stating that 2 + 2 = 5 and a generally accepted and mathematical proven theorem stating 2 + 2 = 4, then one of them must be false.

And remember: Bell’s theorem has absolutely nothing to do with "elementary optics" or any other "optics", I repeat – absolutely nothing. Period.

 

[zonde]

Absolutely not. The statistics, as stated, are in fact predicated on completely randomized polarizations coming from the source. However, if the photons coming from the source were 50% H and V, strictly at those 2 polizations, it would have the same statistical effect, because the rate photons switch paths from H is the same rate they would switch from V in reverse.

But the fact remains, purely randomed polarization would have the same statistics. I went to great lengths to verify this assumption.


Yep, but this is quiet different from random polarizations, where any setting of the PBS sends 50% in each direction, but also incidentally matches, at all PBS settings, the statistics as two pure polarizations at 90 degree offsets.

Consider this: Add the first and second set of 5 second runs together and the 85% and 15% wash out, just like what you initially specified above. Now check and see that the same thing happens at all settings. Thus if it always washed out at all settings in the strict H and V cases, why would a completely randomized source, which only changes those same settings via the photons rather than polarizer settings lead to anything different in the overall statistics?

Yep, but only if the photon from the source are not randomized, which you falsely assumed my description didn't do, simply because the overall statistics happen to match for both pure H and V and randomized photon polarization cases.


The only mistake I see in your reasoning is thinking that because there is a statistical match between the pure H and V case, and the randomized case, I must have only have been referring the pure H and V case. This is wrong. Check the same statistics for the randomized case and you'll see a statistical match for both cases, but the randomized case would invalidate your +45° and -45° case, because I was assuming the randomized case.

Hmm, you think that I am questioning 50%/50% statistics?
I don't do that. I am questioning your statement that "it's reasonable to say ~15% that would have went left go right, and visa versa."
That is not reasonable or alternatively it is reasonable only if you assume that you have source with even mixture of H and V photons.
If you have source that consists of even mixture of photons with any polarization then reasonable assumption is that ~25% changed their channel.