A Understanding Barandes' microscopic theory of causality

[pines-demon]

This post is a spin-off of the original post that discussed Barandes theory, A new realistic stochastic interpretation of Quantum Mechanics, for any details about the interpretation in general PLEASE look up for an answer there.

Now I want this post to focus on this pre-print:

• J. A. Barandes, "New Prospects for a Causally Local Formulation of Quantum Theory", arXiv 2402.16935 (2024)

My main concerns are that Barandes thinks this deflates the anti-classical Bell's theorem. In Barandes, words:

By invoking this microphysical notion of causation, one can formulate a more straightforward criterion for causal locality than Bell’s principle of local causality. As this paper has shown, quantum theory, regarded as a theory of unistochastic processes, satisfies this improved criterion, and is therefore arguably a causally local theory. Remarkably, one therefore arrives at what appears to be a causally local hidden-variables formulation of quantum theory, despite many decades of skepticism that such a theory could exist

See Conclusion section.

I do not know how Barandes can claim this and walk away with it. Bell's theorem has been discussed many times and finding a way to bypass it could be either a major breakthrough or a big NO to Barandes theory. I have reviewed popular videos by Barandes in the previous thread and I do not think he has said a word about it aside from pointing to this pre-print.

Other things to say:

• Barandes overview of the history of Bell theorem is on-point. He clearly seems to understand the evolution of the theorem. He has made some less-nuanced claims about Reichenbach principle and Bell but he has commented on that mistake. See this post.
• Barandes seems to distinguish and focus on causal locality (the idea that faster than light influences are not possible), instead of Bell's local causality. He redefines the terms but it makes me wonder if he implicitly is just proving the no-signaling theorem and calling it a day.
• My main concerns are sections V to VII. In this section he tries to see causal locality in a Bayesian network analogy. I would like to understand some version of it.
• His new microscopic principle of causality is defined as:
  

  A theory with microphysical directed conditional probabilities is causally local if any pair of localized systems $Q$ and $R$ that remain at spacelike separation for the duration of a given physical process do not exert causal influences on each other during that process, in the sense that the directed conditional probabilities for $Q$ are independent of $R$, and vice versa.

How can we understand entanglement under Barandes interpretation? How is this different from Bell's? What are the implications, can he say that now everything is deterministic and "locally causal" as in Bell's terminology? Or is he violating one of Bell's assumptions?

 

[javisot]

The following is my interpretation of what Barandes means.

We can try to understand QM in terms of locality and Einsteinian causality (which doesn't end well), or,
we can say that those concepts aren't fundamental. The correct and fundamental notions of those concepts arise from QM, not from GR. Barandes doesn't even bother to translate "entanglement" into this new language, since entanglement is something that arises when we classically observe QM.

I have the feeling that describing the universe from Barandes's interpretation would produce a very exotic universe from the point of view of GR.

 

[pines-demon]

The following is my interpretation of what Barandes means.

We can try to understand QM in terms of locality and Einsteinian causality (which doesn't end well), or,
we can say that those concepts aren't fundamental. The correct and fundamental notions of those concepts arise from QM, not from GR. Barandes doesn't even bother to translate "entanglement" into this new language, since entanglement is something that arises when we classically observe QM.

Just dropping some terminology does not mean that it bypasses the weirdness of quantum mechanics or anything that is already established. Also it does not mean that now QM more classical because of that.

I have the feeling that describing the universe from Barandes's interpretation would produce a very exotic universe from the point of view of GR.

Then let's understand it better and not just call it a day.

 

[javisot]

Then let's understand it better and now just call it a day.

So, the only one who can answer your question is Barandes. Have you tried calling him?

 

[pines-demon]

So, the only one who can answer your question is Barandes. Have you tried calling him?

I am waiting a bit, I am trying to get a more precise picture instead of sending him a message saying "what's all this??".

 

[DrChinese]

• Barandes’ new microscopic principle of causality is defined as:
  

  A theory with microphysical directed conditional probabilities is causally local if any pair of localized systems and that remain at spacelike separation for the duration of a given physical process do not exert causal influences on each other during that process, in the sense that the directed conditional probabilities for are independent of , and vice versa.

Pines Demon:
Yes, this is precisely the spot at which it becomes clear as you say: let’s redefine Signal Locality as Locality and call it a day.

Of course that is meaningless to the real Bell. And yields nothing of benefit.

When there are random outcomes at a single location, there can be no visible change in conditional probability without knowing more information. Otherwise you could signal FTL.

Nonlocality in QM expresses itself differently. For spin correlation, it is a sin/cos and possibly a square function. Cos^2(theta) for example for photons. The key thing is that the only variable is theta. Theta being *future* settings of distant measurement devices. Nothing else.

If you didn’t know any better: You’d think the future affects the past. And you would never think c was a factor. Notice also that there can be no difference between the predictions of QM vs. QFT.

Funny that… Of course we all know better, right?

 

[Fra]

• My main concerns are sections V to VII. In this section he tries to see causal locality in a Bayesian network analogy. I would like to understand some version of it.
• His new microscopic principle of causality is defined as:

How can we understand entanglement under Barandes interpretation? How is this different from Bell's? What are the implications, can he say that now everything is deterministic and "locally causal" as in Bell's terminology? Or is he violating one of Bell's assumptions?

I think think is a good focus, but it has proven diffculty to explain. It does IMO involve a paradigm shift, which may require pushing things beyond Barandes paper. I'll reread his papers and see if i can explain it better than in previous threads. But IMHO, Baranders TYPE of hidden variables are not of the type in Bells' theorem. So I would say he violates the implicit assumption of "divisibility" into an objective beable. It can for at at least be best understood as a network or a population of bayesian systems(agents=subsystems).

I know you didn't associate well to this as I wrote about it in previous threads. I'll try to see if there is a way to express it more clearly. But understanding the principles of the paradigm is one think, and seeing it EXPLICITLY as applied to a model of particcle physics requires nothing less than reformulation one SIDE of baranders correspondence, into something else - which does not exists yet[and implies a new theory]. But I think one can understand the principles without the missing details, but only with an open mind! If one goes into this, trying to shoot down his ideas, it will be very difficulty to appreciate it. Do we want to understand, or do we want to shoot down?

I'll be back after thinking on how to convey this better.

/Fredrik

 

[Fra]

What are the implications, can he say that now everything is deterministic

No. Baranders formulation retains the irreducible randomness as QM. The purpose of the interpretation is not to restore determinism.

"it will be important to be keep in mind the distinction between deterministic hidden-variables theories and stochastic hidden-variables theories"
-- p22, https://arxiv.org/abs/2302.10778

and "locally causal" as in Bell's terminology?

We still have the kind of non-causality as Bells defines it. But I think Barandes explains why this is not problematic - by introducing a "better" definition of "causal locality".

I don't see it as wordplay or just redefining terms, I happen to find Barandes notion to be the one more useful in my own interpretation.

"A theory with microphysical directed conditional probabilities is causally local if any pair of localized systems Q and R that remain at spacelike separation for the duration of a given physical process do not exert causal influences on each other during that process, in the sense that the directed conditional probabilities for Q are independent"
-- p11, arXiv 2402.16935

For me to say that the conditional probabilities of two subsystems are independent, is simply the same as to say that the stochastic behaviour of "system Q (~ Agent Q)" depends on it's own configuration. (subjective beables), and NOT on the beables (configuration) of R (~Agent R). This is exactly what I would expect from an "intrinsic perspective".

I would say that each subsystems stochastic evolution is represented by a bayesian network; at least differentially (to ignore large time evolution).

But quantum weirdness appears when we observer tow such "stochastic subsystems" interacting. In particular when they have an inteaction history, and can have correlated hidden variable. But I don't see this this hidden variable is not an objective beable, so it is not the lamba in bells ansatz. It would not make sense to partition the transition probability of the composite system, by this subjective beable.

As I see the the correlation between the two systems (in entanglement) in Baranders picture, does NOT predetermined the outcomes when they are inteacting with additional systems (such as detectors), but their behavioural responses to the environment will be pre-correlated to explain the correlation of results, for any detector settings.

This is how i understand it conceptually, in the new paradigm. But note, that Barandes does not provive a DETAILED model, or first principle proof of this, in the "unistochastic" picture constrained by the time evolution of the transition matrices - this is an open problem IMO. This is where I want to see more. But I can appreciate the picture, even without this beeing on the table. I think others may not.

Or is he violating one of Bell's assumptions?

The ansatz in bells theorem, is not valid for the "subjective beables", as they can't be used to paritition or divide the transitions. That ansatz is in as far as I understand this, only valid for "objective beables" that has an element of objective reality (though hidden). I don't see the how the collection of all configuration spaces of every subsytems are objective beables.

To argue in detail for this, I find hard, without the revised theory. But I think Barandes himself does not have all answers, and en enourages people to explore with this "corresponende" means for certain systems.

/Fredrik

 

[PeterDonis]

Barandes thinks this deflates the anti-classical Bell's theorem.

It doesn't. What Barandes calls "a causally local hidden-variables formulation of quantum theory" violates the Bell inequalities (in the paper he uses the CHSH inequalities instead, but it amounts to the same thing) and therefore violates at least one of the premises of Bell's theorem. Bell's theorem is a mathematical theorem: anything that satisfies its premises must satisfy its conclusion.

In other words, a model that is "causally local" in Barandes's sense is "nonlocal" in the sense of violating the Bell inequalities under appropriate conditions. Which has nothing whatever to do with physics; it's just playing with words. Nothing in this wordplay makes the experimentally confirmed behavior of entangled systems any less mysterious.

 

[PeterDonis]

he tries to see causal locality in a Bayesian network analogy

All this seems to me like a dodge if its intent is to claim that this is some kind of fundamental breakthrough. He's not offering an actual model of "what's really happening" at a fundamental level. All of the probabilities are epistemic--i.e., he is using (though he doesn't emphasize this) the standard ignorance interpretation of probabilities, where they arise from our lack of knowledge of the underlying dynamics. "Stochastic dynamics" is just another way of saying the same thing--we don't actually know what's going on at a fundamental level, but we can describe it, on some level, using these stochastic equations. "Bayesian network" is just another way of describing the same thing, i.e., of saying we don't actually know the underlying dynamics. And stopping there, as Barandes seems to want to do, looks to me like just another form of the Copenhagen interpretation: we can never know "what's really going on", the most we can ever know is a description that is equivalent to the standard QM description and tells us probabilities of measurement results, but no more.

 

[Fra]

It doesn't. What Barandes calls "a causally local hidden-variables formulation of quantum theory" violates the Bell inequalities (in the paper he uses the CHSH inequalities instead, but it amounts to the same thing) and therefore violates at least one of the premises of Bell's theorem. Bell's theorem is a mathematical theorem: anything that satisfies its premises must satisfy its conclusion.

In other words, a model that is "causally local" in Barandes's sense is "nonlocal" in the sense of violating the Bell inequalities.

I agree.

Nothing in this wordplay makes the experimentally confirmed behavior of entangled systems any less mysterious.

But , the mystery seems to originate from that we seem to lack a detailed causal mechanism for how the physical interactions actually work; in particular in the entanglment experiments. And as Baranders also noted in some talks, the normal dynamical law, working on an objective state space giving rise to the block universe picture, is problematic for even making a sensible notion of causation, becase the future is determined already.

Isn't Baranders really suggesting that dynamical law, at some point would be relace by stochastic interactions between parts? This is a different paradigm to me. But importantly, not a stochstic process happening in objective beable space, its independent process of spacelike separated parts.

"Interestingly, this connection between the directedness of a Bayesian network’s basic conditional probabilities and the asymmetry of cause-and-effect also sheds light on why causal language is so fraught in the context of theories that are based on microphysical laws that are deterministic and reversible. In a deterministically reversible theory, if a value a of a variable A implies a corresponding value b of another variable B, then p(b|a) = 1, and, in addition, any contingent standalone probability p(a) assigned to a will necessarily equal the contingent standalone probability p(b) assigned to b. It follows immediately
from Bayes’ theorem that p(a|b) = p(b|a) = 1, so these conditional probabilities are not directed, and
the asymmetry of cause-and-effect relationships is lost."
-- p11, arXiv 2402.16935

/Fredrik

 

[pines-demon]

In other words, a model that is "causally local" in Barandes's sense is "nonlocal" in the sense of violating the Bell inequalities under appropriate conditions. Which has nothing whatever to do with physics; it's just playing with words. Nothing in this wordplay makes the experimentally confirmed behavior of entangled systems any less mysterious.

Barandes has an interpretation, its interpretation violates Bell inequalities, so his interpretation violates one of the assumptions of Bell's theorem, the question is now which is it?

If Barandes is just showing that quantum mechanics (AND his interpretation) does not violate some other property (causal locality) then what is its interest for other interpretations?

 

[pines-demon]

No. Baranders formulation retains the irreducible randomness as QM. The purpose of the interpretation is not to restore determinism.

"it will be important to be keep in mind the distinction between deterministic hidden-variables theories and stochastic hidden-variables theories"
-- p22, https://arxiv.org/abs/2302.10778


We still have the kind of non-causality as Bells defines it. But I think Barandes explains why this is not problematic - by introducing a "better" definition of "causal locality".

I don't see it as wordplay or just redefining terms, I happen to find Barandes notion to be the one more useful in my own interpretation.

"A theory with microphysical directed conditional probabilities is causally local if any pair of localized systems Q and R that remain at spacelike separation for the duration of a given physical process do not exert causal influences on each other during that process, in the sense that the directed conditional probabilities for Q are independent"
-- p11, arXiv 2402.16935

For me to say that the conditional probabilities of two subsystems are independent, is simply the same as to say that the stochastic behaviour of "system Q (~ Agent Q)" depends on it's own configuration. (subjective beables), and NOT on the beables (configuration) of R (~Agent R). This is exactly what I would expect from an "intrinsic perspective".

Ok, so no determinism. Would it be safe to say he has nonlocal stochastic hidden variables? This is where I block, maybe Barandes wants to discuss everything in other categories but that does not exclude his interpretation from being discussed in existing categories.

 

[pines-demon]

All this seems to me like a dodge if its intent is to claim that this is some kind of fundamental breakthrough. He's not offering an actual model of "what's really happening" at a fundamental level. All of the probabilities are epistemic--i.e., he is using (though he doesn't emphasize this) the standard ignorance interpretation of probabilities, where they arise from our lack of knowledge of the underlying dynamics. "Stochastic dynamics" is just another way of saying the same thing--we don't actually know what's going on at a fundamental level, but we can describe it, on some level, using these stochastic equations. "Bayesian network" is just another way of describing the same thing, i.e., of saying we don't actually know the underlying dynamics. And stopping there, as Barandes seems to want to do, looks to me like just another form of the Copenhagen interpretation: we can never know "what's really going on", the most we can ever know is a description that is equivalent to the standard QM description and tells us probabilities of measurement results, but no more.

Epistemic or not he has claimed to have a "real" interpretation in the sense that there is some kind of classical mechanics going on in the background.

 

[javisot]

Ok, so no determinism. Would it be safe to say he has nonlocal stochastic hidden variables? This is where I block, maybe Barandes wants to discuss everything in other categories but that does not exclude his interpretation from being discussed in existing categories.

From "the stochastic-quantum correspondence", section H "Entanglement":

Barandes- "This analysis precisely captures the quantum-theoretic notion of entanglement. Systems that interact with each other start to exhibit what appears to be a nonlocal kind of stochastic dynamics, even if the systems are moved far apart in physical space, and decoherence by the environment effectively causes a breakdown in that apparent dynamical nonlocality. This stochastic picture of entanglement and nonlocality provides a new way to understand why they occur in
the first place. The indivisible nature of generic stochastic dynamics could be viewed as a form of nonlocality in time, which then leads to an apparent nonlocality across space. A division event leads to an instantaneous restoration of locality in time, which then leads to a momentary restoration of manifest locality across space."

 

[javisot]

"Systems that interact with each other start to exhibit what appears to be a nonlocal kind of stochastic dynamics", I suppose by this he "translate" the strangeness of QM.

 

[pines-demon]

From "the stochastic-quantum correspondence", section H "Entanglement":

Barandes- "This analysis precisely captures the quantum-theoretic notion of entanglement. Systems that interact with each other start to exhibit what appears to be a nonlocal kind of stochastic dynamics, even if the systems are moved far apart in physical space, and decoherence by the environment effectively causes a breakdown in that apparent dynamical nonlocality. This stochastic picture of entanglement and nonlocality provides a new way to understand why they occur in
the first place. The indivisible nature of generic stochastic dynamics could be viewed as a form of nonlocality in time, which then leads to an apparent nonlocality across space. A division event leads to an instantaneous restoration of locality in time, which then leads to a momentary restoration of manifest locality across space."

Thanks for the quote. Assuming this means that his interpretation is nonlocal, then it is no much different to Bohmian mechanics, in this sense it could be an improvement as that there is a more powerful mathematical equivalence and hopefully no preferred basis (right?). But then, if I am not being too reductive, I can think of Barandes interpretation as replacing the pilot wave by a nonlocal permeating stochastic force field that is all over space and acts instantaneously. This is to me not deflationary at all.

 

[javisot]

Thanks for the quote. Assuming this means that his interpretation is nonlocal, then it is no much different to Bohmian mechanics, in this sense it could be an improvement as that there is a more powerful mathematical equivalence and hopefully no preferred basis (right?). But then, if I am not being too reductive, I can think of Barandes interpretation as replacing the pilot wave by a nonlocal permeating stochastic force field that is all over space and acts instantaneously. This is to me not deflationary at all.

I completely agree with what Peter Donis says, even if what Barandes proposes is true and his interpretation can be considered "canonical", it does not discover anything new nor does it help to better explain anything old.

 

[PeterDonis]

the mystery seems to originate from that we seem to lack a detailed causal mechanism for how the physical interactions actually work

I think that's one way of stating it, yes.

Isn't Baranders really suggesting that dynamical law, at some point would be relace by stochastic interactions between parts?

That's just another way of saying what you said in the first quote above--"stochastic interactions between parts" isn't a "detailed causal mechanism", it's just a description of our ignorance about such a thing.

 

[PeterDonis]

I can think of Barandes interpretation as replacing the pilot wave by a nonlocal permeating stochastic force field that is all over space and acts instantaneously

But a "stochastic force" is just another way of saying "we don't understand what's actually going on". The pilot wave is deterministic; probabilities arise because of our ignorance of the actual microphysical state (the particle positions in the usual formulation of Bohmian mechanics). Saying that probabilties are fundamental, that the only dynamics we can have is "stochastic", is saying we can't know what's actually going on--in other words, another form of Copenhagen, as I said in an earlier post.

 

[javisot]

Is there any relationship between stochastic dynamics and the uncertainty principle?

I mean, Barandes assumes that particles have defined properties (the uncertainty principle doesn't directly affect their properties), but Barandes also claims that his interpretation is "canonical" in the sense of "being a Copenhagen," so the uncertainty principle should be expressed in some way in stochastic dynamics (is that correct?)

From "the stochastic-quantum correspondence", "introduction":

"Taking a more foundational perspective, this paper also uses the stochastic-quantum correspondence to show that physical models based on configuration spaces combined with stochastic dynamics can replicate all the empirical predictions of textbook quantum theory—including interference, decoherence, entanglement, noncommutative observables, and wave-function collapse—"


I'm looking for an analogy to show what Barandes is proposing. Suppose we want to explain QM using golf as an analogy, we'll say that the ball has no defined properties, and when you hit it...etc.

Barandes, on the other hand, tells us, "Imagine that the golf ball has defined properties, but the club with which we hit the ball has no defined properties."

 

[Fra]

Would it be safe to say he has nonlocal stochastic hidden variables?

No, not as I think you mean it. As Barandes even notes, Bell himself in the 1975 paper generalized the argument from deterministic to stochastic HV, so instead of thinking that the outcomes are determined by the hidden variable, a probability distribution is determined. But it's important to note that the "stochastics" is still relative to the objective beables.

Bell's picture is about marginalizing over the HV. This is not how Barandes picture works. The HV in Barandes view is the configurations of the subsystems. These are beables for each subsytem. They are not objective beables.

Bell implicitly assume that the hidden varible is a classical probability space with divisible markovian dynanamics. Barandes "generalized stochastic" is not divisible, this is where the ansatz in bells theorm does not apply to Barandes picture.

This is where I block, maybe Barandes wants to discuss everything in other categories

I think he does for a reason, that in different categories or paradigms, the picture may be more clear. After all his motivation is that the hilber picture is indeed mystic or hard to understand. Not necessarily hard to USE in the pragmatic sense, but hard to conceptaully make sense of.

I think Barandes pictures may be harder to understand, if you insist on discussing it in terms of inappropriate categories.

For me, it makes most sense in terms of "bayesian networks" associated to agents, and I associate any subsystem = an agent, and then these subsystems may interact. And this is when "quantum weirdness" happens - when described from a third external observer, because then the "configurations" of the two subsystems are no longer beables, toi the external observer.

/Fredrik

 

[Fra]

That's just another way of saying what you said in the first quote above--"stochastic interactions between parts" isn't a "detailed causal mechanism", it's just a description of our ignorance about such a thing.

No, that's exacatly what I think is a misinterpretation of Barandes suggestion.

The whole point with the indivisbility is that the the stochastic process in Barandes view is NOT an "ignorance". "ignorance" is what Bells' theorem is about.

I think the stochastics in Baranders view is irreducible, and the explicit manifestation of that, is that it is not divisible in terms of "ignorance" of objective beables.

The best way I could describe this is that, in Barandes view, we do not have ONE stochastic process. There is an "independent" stocahstic process going on at each subsystem. This can not be described in terms of "ignorance" of an external observer.

/Fredrik

 

[PeterDonis]

The whole point with the indivisbility is that the the stochastic process in Barandes view is NOT an "ignorance".

Quibble. The key point is here:

I think the stochastics in Baranders view is irreducible

And that means that there is no "detailed causal mechanism" at all. It does not mean that, well, "stochastics" is good enough for a detailed causal mechanism so we don't need to look any further. It means looking any further is pointless because it is impossible to find what we're looking for. We simpl have to accept that there is no "detailed causal mechanism" there at all for us to find.

 

[PeterDonis]

The best way I could describe this is that, in Barandes view, we do not have ONE stochastic process. There is an "independent" stocahstic process going on at each subsystem. This can not be described in terms of "ignorance" of an external observer.

Sure it can--the "observer" is just another subsystem. There is nothing logically impossible about that subsystem not having access to details of what's going on in other subsystems that would be needed to do better than "stochastics" at predicting what other subsystems will do.

What Barandes is really claiming, as you describe it, is that those other details do not exist. If "ignorance" is not a good word to describe Barandes's interpretation, that is the reason--that it's not that those details are there and we just don't know them, it's that they're not there at all. It has nothing to do with things like using Bayesian networks to describe the probabilities instead of something else. It's a fundamental claim about what simply doesn't exist in "reality", independent of any of our descriptions.

 

[javisot]

If there's no causal mechanism behind entanglement, why are some particles entangled and others not? If there's no causal mechanism, they could all be entangled.

But we know that's not true; not all particles are entangled.

(MoE?, what's MoE for Barandes?)

 

[Fra]

And that means that there is no "detailed causal mechanism" at all. It does not mean that, well, "stochastics" is good enough for a detailed causal mechanism so we don't need to look any further. It means looking any further is pointless because it is impossible to find what we're looking for. We simpl have to accept that there is no "detailed causal mechanism" there at all for us to find.

I think we lost the focus a bit. Let me explain. Barandes indeed does not suggest a "mechanism" that restores the randomess of certain things. We agree there. (Except for that the transition matrix, certainly begs for an "explanation" which is missing from his picture - but its because he has a correspondence only - not yet a full first-principle reconstruction, it is indeed irreducible - from the perspective of the subsystems stochastics.)

But this was not the "mechanism" I think we discussed in the thread. The "mechanism" I refers to is to exaplain, not the outcomes, but ONLY the correlation of outcomes. In Bells paradigm, that requires predicting the outcomes as well, or a distribution of them. I see the Baranders pictures suggest a way for a "mechanism" for correlations, while keeping the irreducible interderminism. This is different from bohmian mechanics.

But to explain it convincingly to doubters - I think one needs to find a first principle construction(until that is in place, it is admittdely some handwaving, this is why we are left discussing conceptual princiiples of paradigm and not explicit models, so i think that is exactly what the "interpretational" things are) - not just rely on the "correspondence". It is suggestive, the the mission is not completed yet, so in this sense I agree that hte correspondence alone is not the final solution, but I think unlike others that it is a good step towards a new perspective, that helps.

/Fredrik

 

[jbergman]

This post is a spin-off of the original post that discussed Barandes theory, A new realistic stochastic interpretation of Quantum Mechanics, for any details about the interpretation in general PLEASE look up for an answer there.

Now I want this post to focus on this pre-print:

• J. A. Barandes, "New Prospects for a Causally Local Formulation of Quantum Theory", arXiv 2402.16935 (2024)

My main concerns are that Barandes thinks this deflates the anti-classical Bell's theorem. In Barandes, words:

See Conclusion section.

I do not know how Barandes can claim this and walk away with it. Bell's theorem has been discussed many times and finding a way to bypass it could be either a major breakthrough or a big NO to Barandes theory. I have reviewed popular videos by Barandes in the previous thread and I do not think he has said a word about it aside from pointing to this pre-print.

Other things to say:

• Barandes overview of the history of Bell theorem is on-point. He clearly seems to understand the evolution of the theorem. He has made some less-nuanced claims about Reichenbach principle and Bell but he has commented on that mistake. See this post.
• Barandes seems to distinguish and focus on causal locality (the idea that faster than light influences are not possible), instead of Bell's local causality. He redefines the terms but it makes me wonder if he implicitly is just proving the no-signaling theorem and calling it a day.
• My main concerns are sections V to VII. In this section he tries to see causal locality in a Bayesian network analogy. I would like to understand some version of it.
• His new microscopic principle of causality is defined as:

How can we understand entanglement under Barandes interpretation? How is this different from Bell's? What are the implications, can he say that now everything is deterministic and "locally causal" as in Bell's terminology? Or is he violating one of Bell's assumptions?

I should dig into this paper but don't have the time. I did want to say that Bayesian networks have very strong markovian properties which his unistochastic processes don't have, so I am not sure what the analogy is here.

 

[PeterDonis]

Barandes indeed does not suggest a "mechanism" that restores the randomess of certain things. We agree there.

Which means that, by your own admission, Barandes does not solve what you yourself said was the mystery.

The "mechanism" I refers to is to exaplain, not the outcomes, but ONLY the correlation of outcomes.

But, as I've already said, "something something stochastic something something" is not a mechanism. It's just a description. It doesn't explain the correlations. It just describes them.

 

[Morbert]

Re/ Barandes and Copenhagen:

The Copenhagen interpretation (to the extent that it is a single interpretation) does not have a microscale ontology. You cannot assert existing-but-unknown microscopic properties. Instead, it asserts macroscopic preparation protocols, tests, and responses.

Barandes's unistochastic interpretation has a microscale ontology. You can assert existing-but-unknown microscopic properties on which measurement outcomes supervene.

Re/ Barandes and Bell:

Barandes does not dispute Bell's theorem. He instead rejects it as a good basis for a theory of local microphysical causation, and offers an alternative (and, Barandes has remarked, more complete) theory.

-

Ultimately the novelty to Barandes's approach seems to be to move inseparability from states to dynamics. This lets him recover both a microscale ontology and a consistent, unambiguous model of microphysical causality and a principle of local causality.