I A new realistic stochastic interpretation of Quantum Mechanics

[Fra]

I think one reason this is hard to understand is because we implicitly but repeatedly confuse normative/guiding P of possibilities and descriptive P of what actually happened historically.

Histories don't interfere. Interference lies in how guiding probabilities account for possibilities and uncertainties of the future.

In inference its important to not mix the concepts. This is closely related to what barandes label the "category error" or "category problem".

Ie. If you keep thinkning of the transition probabilites as descriptive, it gets wrong. But if you think of them as guiding P for an agent taking stochastic actions, it makes more sense.

The flawed application of common cause in bells ansatz is easier to spot if you think in terms of guiding probabilities of agent/observer - which of course, like barandes thinks, is a physical system. One just have to not confuse this with thinking that means there is an exteral view of all this. It is beacause it does not, that makes the guiding view of P more fundamental.

/Fredrik

 

[Fra]

calling it an interpretation is flawed at this stage, it is like calling a Wick rotation an interpretation.

I partly agree with this. But I think he highlights important things, and changing stance that can make future development eaiser. He points out the obvious flaw in bells ansatz, that was there all along but which few speak of. Its in the talk RUTA posted way back in the thread sa well.

/Fredrik

 

[pines-demon]

In two of Barandes' papers he mentions the mechanism for entanglement being the fact that correlations induced by local interactions between two different stochastic systems are remembered over time until the system is later disturbed (e.g. by measurement devices), after which it basically forgets what had happened in the past at the original local interaction. This is purely because the indivisible transition matrix is non-Markovian - divisibility or division events means it no longer has these memory properties. There is no superdeterminism because the correlation is solely due to the local interaction. Any correlations in the measurement devices are solely due to the fact that the correlation from the original local interaction is remembered; the devices do not causally influence each other over distances independently of this. It is very general though. His entanglement examples I don't think give strong insight to entangled polarization / spin experiments.

You say it is not superdeterminism but as you put it, it sounds like it is. You say that measurement devices do not necessarily interact with each other instantaneously (so it is not some nonlocal faster-than-light interaction), but it is more of like past event thing

There is no superdeterminism because the correlation is solely due to the local interaction. Any correlations in the measurement devices are solely due to the fact that the correlation from the original local interaction is remembered

Does that means that all measurement devices interacted once in the past so measurements are not independent [a.k.a aka superdeterminism]? If it is not this, what is it? Is there a way I can think about it aside from "indivisible non-Markovianity"?

 

[Fra]

"Not statistically independent" does not imply superdeterminism. Superdeterminism is a special extremal case.

Just as in bell experiments, the "memory" explains the correlation - it does not determine the full results, because they involve detector settings too.

So the full interaction is then conceptually an interaction between
1. a system (that is remebers a relation to its correlates partner)
2. The detector that is ignorant about this, and thus acts stochastically based on "preparation info" only - which is "public"

The combination fo this will have elements of chance; and be influenced by detector choices; but also partially influenced by the "memory" of incoming system.

For me this is conceptually quite clear. What is missing is the mathematical modell of this from that perspective.

IMO, what prevents superdeterminism conceptually is that the memory of systems are limited; thus over time some model with lossy retention seems required. Only maybe an observer beeing a black hole can retain most without loss by growing mass.

But this is all future possible developments not lined out by Barandes. But de does say thar he thinks there may be link to this and future QG. It is in the same talk in rutas post.

/Fredrik

 

[pines-demon]

I partly agree with this. But I think he highlights important things, and changing stance that can make future development eaiser. He points out the obvious flaw in bells ansatz, that was there all along but which few speak of. Its in the talk RUTA posted way back in the thread sa well.

/Fredrik

I rewatched that part today and now I am more skeptic. To get Bell's inequality one needs several ingredients, mainly statistical independence (violations lead to superdeterminism) and factorizability. There are several ways to get factorizability. Bell had two different ways, one appears in Bell's later work and is called local causality. The other is indeed Reichenbach's common cause principle (not used by Bell). Either way, standard quantum mechanics violates this factorizability.

Barandes finds that his theory also violates this factorizability and claims that it is a violation of Reichenbach principle (it could very well be). But it could be very well that it is a violation of local causality making Barandes' interpretation nonlocal (in the Bell way, like in the case of Bohmian mechanics). In his lecture he conflates the Bell's local causality with Reichenbach' common cause (saying that is what Bell used) so I do not think he is into something there.

 

[pines-demon]

"Not statistically independent" does not imply superdeterminism. Superdeterminism is a special extremal case.

It is kind of the definition. That comment was aimed at iste who claimed that the correlations result from the the interactions of the detectors in the past . This is usually what superdeterminism claims (maybe iste did not meant that but to say interactions between the entangled particles instead).

 

[Fra]

It is kind of the definition. That comment was aimed at iste who claimed that the correlations result from the the interactions of the detectors in the past . This is usually what superdeterminism claims

Determinism means the future is predetermined. At least in principle - modulo deterministic chaos. Superdetermimism take this to include even choices of experimenters.

That is not what the memory thing implies. The problem with bells ansatz lmo does NOT(edit) save determinism.

/Fredrik

 

[pines-demon]

Determinism means the future is predetermined. At least in principle - modulo deterministic chaos. Superdetermimism take this to include even choices of experimenters.

While superdeterminism does imply determinism it is not exactly that what is meant by that term. At least in this context it is a statistical property, statistical independence (no superdeterminism) it is the ability to average out any correlations between the measuring devices (make many trials, create the measuring devices in different factories, put them far apart, make the setting dependent on nuclear random number generators). It is important in science because that's why experiments can be repeated. Mathematically, superdeterminism means that a representative distribution of your hidden parameters $\lambda$ depend on the settings $x,y$ of your measuring devices, i.e.
$$\rho(\lambda|x,y)\neq\rho(\lambda).$$
It is called superdeterminism because all measuring devices of the observable universe interacted at some point in the past if not in the Big Bang, so the correlations would be set from early in the past (conspiracy).
Edit: funny enough there are Bell tests that put constraints to superdeterministic theories by deciding the settings of the measurement devices based on thermal radiation from very distant galaxies.

 

[iste]

You say it is not superdeterminism but as you put it, it sounds like it is. You say that measurement devices do not necessarily interact with each other instantaneously (so it is not some nonlocal faster-than-light interaction), but it is more of like past event thing

Does that means that all measurement devices interacted once in the past so measurements are not independent [a.k.a aka superdeterminism]? If it is not this, what is it? Is there a way I can think about it aside from "indivisible non-Markovianity"?

No, measurement devices didn't interact in past. Particles interact in the past before they are measured, causing a correlation between them which is preserved when the particles are separated and subsequently measured. Measurement devices don't interact with each other or anything else before the measurement of the particles. But obviously this doesn't incorporate measurement settings so maybe it is missing something that could account for what you are possibly thinking about.

Barandes finds that his theory also violates this factorizability and claims that it is a violation of Reichenbach principle

From the paper, he seemed to suggest that its not so much that Reichenbach's principle is violated but it isn't applicable to the stochastic description because the third variable needed to formulate it doesn't exist in the stochastic description, even though the straightforward analysis is that the correlation between the particles can be directly attributed to an initial local interaction between the particles that is subsequently remembered even when they are moved far apart, purely because of the non-markovianity of the indivisible transition matrix.

I actually mentioned a source earlier that seems to display this mechanism in a completely different classical hydrodynamical model:

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.7.093604

Droplets interact in the same fluid bath and become correlated so that their dynamics are nonseparable. A barrier is erected which isolates the particles so they can no longer communicate in any way. But despite their isolation, their behavior still maintains correlations between them which can be attributed to the fact that they have been remembered by the now-isolated respective particle-bath systems. This description models quite closely to Barandes' description of entanglement only here it is expicit that there is no non-local communication because its a classical model of just a droplet in a bat which you could build an experiment about. Its not mentioned in the abstract I think but if you look at other sources for these pilot-wave hydrodynamic systems, the reason they have these quantum-like behaviors is that they are non-Markovian and retain memory of the past.

 

[iste]

They are only constrained by their initial and final points. It is in fact somewhat wrong to think about them as paths. They are functions $x(t)$, a function can be totally weird, like $x(t)=0$ for rational $t$ and $x(t)=1$ for irrational $t$. The "path" integral is really the functional integral, i.e. the integral over all functions.

What does weird mean here in terms of paths?

 

[pines-demon]

No, measurement devices didn't interact in past. Particles interact in the past before they are measured, causing a correlation between them which is preserved when the particles are separated and subsequently measured. Measurement devices don't interact with each other or anything else before the measurement of the particles. But obviously this doesn't incorporate measurement settings so maybe it is missing something that could account for what you are possibly thinking about.

Thanks for clarifying what you meant, I quoted a previous text of yours that seemed to suggest the opposite.

From the paper, he seemed to suggest that its not so much that Reichenbach's principle is violated but it isn't applicable to the stochastic description because the third variable needed to formulate it doesn't exist in the stochastic description, even though the straightforward analysis is that the correlation between the particles can be directly attributed to an initial local interaction between the particles that is subsequently remembered even when they are moved far apart, purely because of the non-markovianity of the indivisible transition matrix.

That does not cut it for me. He does not have factorizability that is fine, he can argue about Reichanbach principle all day, but Reichbach vs Bell causal locality is not settled. So he could also just have nonlocality built into it without knowing it. I mean again I would sell his work as a duality, it needs to be worked into an interpretation that can provide a picture of the phenomena.

I actually mentioned a source earlier that seems to display this mechanism in a completely different classical hydrodynamical model:

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.7.093604

Droplets interact in the same fluid bath and become correlated so that their dynamics are nonseparable. A barrier is erected which isolates the particles so they can no longer communicate in any way. But despite their isolation, their behavior still maintains correlations between them which can be attributed to the fact that they have been remembered by the now-isolated respective particle-bath systems. This description models quite closely to Barandes' description of entanglement only here it is expicit that there is no non-local communication because its a classical model of just a droplet in a bat which you could build an experiment about. Its not mentioned in the abstract I think but if you look at other sources for these pilot-wave hydrodynamic systems, the reason they have these quantum-like behaviors is that they are non-Markovian and retain memory of the past.

This for me would do the work [if understood], in the sense that if he can come up with a SIMPLE classical picture of his phenomena he would be able to provide an interpretation. However I cannot access or assess this paper and I would not be too surprised if real fluid systems have weird non-linear effects lead to wrong conclusions. That's why I think a toy model with a single qubit could clarify the situation.

 

[Demystifier]

What does weird mean here in terms of paths?

The $x$ attains only two values, 0 and 1, without ever attaining any value in between. Moreover, it jumps from 0 to 1 and back infinitely often. The velocity $dx/dt$ is not defined at any $t$.

 

[pines-demon]

The $x$ attains only two values, 0 and 1, without ever attaining any value in between. Moreover, it jumps from 0 to 1 and back infinitely often. The velocity $dx/dt$ is not defined at any $t$.

Just to be clear here the derivative is not defined but has some instantaneous momentum right?

 

[WernerQH]

Droplets interact in the same fluid bath and become correlated so that their dynamics are nonseparable.

But do these experiments produce anything resembling Bell-type correlations? Classical correlations have been understood for ages. It is misleading to wave your hands and talk about "nonseparable" dynamics.

 

[iste]

But do these experiments produce anything resembling Bell-type correlations? Classical correlations have been understood for ages. It is misleading to wave your hands and talk about "nonseparable" dynamics.

The Barandes entanglement example is very rudimentary. I was just implying that given the description of entanglement he gives, there is no need to add any underlying non-local influence; the paper then is an example since it is equally rudimentary. I see that someone may not be as convinced with regard to actual quantum experiments, or even that the indivisibility could be achieved without something else funny going on.

I would not be too surprised if real fluid systems have weird non-linear effects lead to wrong conclusions.

I do note in post #247 that these hydrodynamic models are superficially similar to the interpretation given by Nelson's stochastic mechanics, which is a predecessor that shares the same stochastic interpretation as Barandes' model. But yes, Barandes' model is agnostic of what kind of mechanisn would cause the non-Markovianity... or how weird the mechanism would be. I guess there could be an underlying non-local mechanism but to me it feels like that is like overkill in terms of parsimony by doubling the mechanisms in the picture.

 

[iste]

The $x$ attains only two values, 0 and 1, without ever attaining any value in between. Moreover, it jumps from 0 to 1 and back infinitely often. The velocity $dx/dt$ is not defined at any $t$.

And this is a discontinuous path? I guess it would not be  identical to the stochastic mechanical paths. In the Hiley paper I linked though, they seem to imply they are only considering continuous paths?

 

[pines-demon]

The Barandes entanglement example is very rudimentary. I was just implying that given the description of entanglement he gives, there is no need to add any underlying non-local influence; the paper then is an example since it is equally rudimentary. I see that someone may not be as convinced with regard to actual quantum experiments, or even that the indivisibility could be achieved without something else funny going on.



I do note in post #247 that these hydrodynamic models are superficially similar to the interpretation given by Nelson's stochastic mechanics, which is a predecessor that shares the same stochastic interpretation as Barandes' model. But yes, Barandes' model is agnostic of what kind of mechanisn would cause the non-Markovianity... or how weird the mechanism would be. I guess there could be an underlying non-local mechanism but to me it feels like that is like overkill in terms of parsimony by doubling the mechanisms in the picture.

Just for clarification the first quote is not mine but of WernerHQ. As for the second comment, i have nothing left to add I only hope that this agnosticism is because he is working out the details.

 

[Demystifier]

Just to be clear here the derivative is not defined but has some instantaneous momentum right?

I don't know how to define momentum in this case.

 

[Demystifier]

In the Hiley paper I linked though, they seem to imply they are only considering continuous paths?

They do. In fact, the integral over all paths/functions is mathematically ambiguous (because the limit $\epsilon\to 0$ is ambiguous, where $\epsilon$ is associated with the discretized time), so people define it differently in different contexts.

 

[Fra]

While superdeterminism does imply determinism it is not exactly that what is meant by that term. At least in this context it is a statistical property, statistical independence (no superdeterminism) it is the ability to average out any correlations between the measuring devices (make many trials, create the measuring devices in different factories, put them far apart, make the setting dependent on nuclear random number generators). It is important in science because that's why experiments can be repeated. Mathematically, superdeterminism means that a representative distribution of your hidden parameters $\lambda$ depend on the settings $x,y$ of your measuring devices, i.e.
$$\rho(\lambda|x,y)\neq\rho(\lambda).$$
It is called superdeterminism because all measuring devices of the observable universe interacted at some point in the past if not in the Big Bang, so the correlations would be set from early in the past (conspiracy).
Edit: funny enough there are Bell tests that put constraints to superdeterministic theories by deciding the settings of the measurement devices based on thermal radiation from very distant galaxies.

I have a feeling you miss details and mix up causal influence and determinism. It this another case where bell community reinvent meaning of established words? We know they did to "locality".

Also non-deterministic causality does not logically imply deterministic p- distributions evolution. In standard QM there is determinism at distribution level, but this is not the general case, its excludes reinforced emergence or evolutionary emergence.

How we label things does not bother me but ignoring these logical possibilities makes the analysis meaningless.And if we redfine words to mean something different we only fool ourselves.

/Fredrik

 

[pines-demon]

I have a feeling you miss details and mix up causal influence and determinism. It this another case where bell community reinvent meaning of established words? We know they did to "locality".

Also non-deterministic causality does not logically imply deterministic p- distributions evolution. In standard QM there is determinism at distribution level, but this is not the general case, its excludes reinforced emergence or evolutionary emergence.

How we label things does not bother me but ignoring these logical possibilities makes the analysis meaningless.And if we redfine words to mean something different we only fool ourselves.

/Fredrik

I think we are mixing different arguments into a mesh of partial arguments that lead nowhere. The mathematics of each assumption in the Bell theorem are clear, so any misunderstanding of the assumptions can be solved by writing them mathematically. Is superdeterminism for you some other mathematical assumption? As for determinism, if quantum mechanics or Barandes theory is deterministic is a topic that I have not discussed yet.

 

[Fra]

I think we are mixing different arguments into a mesh of partial arguments that lead nowhere. The mathematics of each assumption in the Bell theorem are clear, so any misunderstanding of the assumptions can be solved by writing them mathematically.

if I just look at the math (decompose and label as one wish), the key mathematical asssumptions of bells ansatz is IMO flawed and simplistic. Bells theorem litteraly disproves a simple "naive" form of hidden variables. Its been a dead horse for me for 25 years.

As for the less naive version bells theorem is of course,correct - it is a mathematical theorem - it just does not apply, and for this is clear. No conspiracya of determinism has anything to dp with that.

Is superdeterminism for you some other mathematical assumption?

Yes it is. It is for me the ultimate determinstic conspiracy. It an sense, if you belive in determinism, then why not superdeterminism? (Then you are at least consistent over complexity scales)

I subscribe to neither however.

/Fredrik

 

[iste]

Just to be clear here the derivative is not defined but has some instantaneous momentum right?

I'll just note that none of the continuous, non-differentiable paths have a well-defined instantaneous momentum either. If you look at the first link to the Hiley paper in #287 they talk about it a bit; its not well-defined becauae generally momenta going into a point and momenta leaving it are not the same and its completely ambiguous which one you would choose if you wanted to define instantaneous momentum - so when they calculate the average path integral trajectory momentum at some point, they have to consider both. And they have a nice picture.

 

[pines-demon]

if I just look at the math (decompose and label as one wish), the key mathematical asssumptions of bells ansatz is IMO flawed and simplistic. Bells theorem litteraly disproves a simple "naive" form of hidden variables. Its been a dead horse for me for 25 years.

That’s on you. You are the one not assigning the usual terminology by not engaging with the usual derivations of the theorem.

As for the less naive version bells theorem is of course,correct - it is a mathematical theorem - it just does not apply, and for this is clear. No conspiracya of determinism has anything to dp with that.

If you are not using the usual terminology it is hard to agree or disagree with you. Please define the assumptions you think are useful mathematically.

Yes it is. It is for me the ultimate determinstic conspiracy. It an sense, if you belive in determinism, then why not superdeterminism? (Then you are at least consistent over complexity scales)

I subscribe to neither however.

/Fredrik

Again if you or I want to believe in it or not it is not the issue. The topic at hand is what Barandes interpretation means, if somebody say it implies X but you disagree thinking that X means Y, then you are going to talk past each other.

The topic of superdeterminism in relation to Barandes was directed at a phrase of another user and that user has now clarified that he did not mean that. So we can move past that topic of superdeterminism. Alternatively you can open a post to discuss what superdeterminism means.

 

[Fra]

Again if you or I want to believe in it or not it is not the issue. The topic at hand is what Barandes interpretation means

Agreed, lets get back to the topic.
Whatever we call it, he points out the issue in the ansatz here,
I posted this link in an older post in thread as well.

What I thought we were going, is to conceptually elaborate on this - it to find a conceptual interpretation of the math. But as we diverged in terminology-disagreement. The question is what perspective to take, that can make the issue barandes points out, more intuitive to understand? The only reasons I like barandes papers and talk, is because I am already tuned in to perspectives which harmonize well with his new perspective. But I also agree that I think he doesn't "explain" in clear enough to convey those not already tune into this. This is what I can't stop wondering what future stuff Baranders has up his sleeves to take this to the next nevel, perhaps relating to unification. If he can show a glipse of that, perhaps the reason for this change of perspective would be easier to accept.

/Fredrik

 

[Fra]

what Barandes interpretation means

As I wrote before I'm not sure I would call it an interpretation either at this point, but his "change of view" from hilbert space to simply transition probabilities, might be more "natural" for certain interpretations, for example my own qbist inspired one. This is why it makes sense to me. I think the hilbert space formalism, is a clever way to make compact math, after all linear algebra is quite "clean" and nice. But it may conceptually obscure the mapping onto the preferred ontology.

/Fredrik

 

[Lord Jestocost]

TL;DR Summary: I attended a lecture that discussed the approach in the 3 papers listed below. It seems to be a genuinely new interpretation with some interesting features and claims.

These papers claim to present a realistic stochastic interpretation of quantum mechanics......

From the conclusion of the paper “Is quantum mechanics equivalent to a classical stochastic process?” by H. Grabert, P. Hänggi and P Talkner (Phys. Rev. A 19, 2440 (1979)):

“In this paper we have analyzed the relations between the theory of stochastic processes and the statistical interpretation of quantum mechanics. We have shown that the Schrödinger evolution is not equivalent to a Markovian process, as claimed in several papers. Possible relations to a non-Markovian process have been investigated, and we have shown that the various correlation functions used in quantum theory do not have the properties of the correlations of a classical stochastic process. This leads to the conclusion that quantum mechanics has little if anything to do with the theory of stochastic processes.” [Bold by LJ]

 

[WernerQH]

From the conclusion of the paper “Is quantum mechanics equivalent to a classical stochastic process?” by H. Grabert, P. Hänggi and P Talkner (Phys. Rev. A 19, 2440 (1979)):

This leads to the conclusion that quantum mechanics has little if anything to do with the theory of stochastic processes.

I don't think that the Grabert et al. paper has ruled out all conceivable stochastic processes. What saves Barandes' papers is that they present more an abstract framework. He hasn't really defined a specific stochastic process.

 

[Fra]

I don't think that the Grabert et al. paper has ruled out all conceivable stochastic processes. What saves Barandes' papers is that they present more an abstract framework. He hasn't really defined a specific stochastic process.

Conceptually I would say the difference must be the "constraints" on stochastic in configuration space the barandes transition probabilities impose on the "stochastic process", to replace the normal physical laws, as this is his take on how "the micrcophysical law" is encoded. If I remember correctly he put it like something like that in one of the talks or paper.

To get some more explanatory value I would expect some mechanis that explaines where this comes from; otherwise they are just as finetuned and unexplained as the hamiltonian. (My personal vision is that they are emergent in bigger picture, but it is not clear what Baranders thinks, I think he just leaves this unresolved which I don't blame hime for, because that is a big question, not quickly resolved I think).

/Fredrik

 

[iste]

From the conclusion of the paper “Is quantum mechanics equivalent to a classical stochastic process?” by H. Grabert, P. Hänggi and P Talkner (Phys. Rev. A 19, 2440 (1979)):

“In this paper we have analyzed the relations between the theory of stochastic processes and the statistical interpretation of quantum mechanics. We have shown that the Schrödinger evolution is not equivalent to a Markovian process, as claimed in several papers. Possible relations to a non-Markovian process have been investigated, and we have shown that the various correlation functions used in quantum theory do not have the properties of the correlations of a classical stochastic process. This leads to the conclusion that quantum mechanics has little if anything to do with the theory of stochastic processes.” [Bold by LJ]

I'm pretty sure the Barandes indivisible process doesn't satisfy the assumptions used in the last section either!