I A new realistic stochastic interpretation of Quantum Mechanics

[physika]

"The idea is that it however has todo with interacting information processing"

"there indeed is a generic phenomena, that exists... ...in self-organizing process... ...and self-organization, naturally happens... ...when the parts process and act upon information about other parts."

As
https://physics.aps.org/articles/v17/s36

 

[DrChinese]

1. So this is second post with quotes. I am nit sure that the first post was tagged to you. So just in case, just letting you know there is another post above which quotes from paper specifically about spin correlations.

2. These authors I will quote... https://arxiv.org/abs/0907.0767

3. We now let only two doctors, one in Lille and one in Lyon perform the examinations...

4. "The mistake here is that Bell and followers insist from the start that the same element of reality occurs for the three different experiments with three different setting pairs. This assumption implies the existence of the combinatorial-topological cyclicity that in turn implies the validity of a non-trivial inequality but has no physical basis. Why should the elements of reality not all be different?"

1. Yes, I saw.


2. I have been following the deRaedt team's work for 15+ years. One of the early members of my list of Bell deniers. I think their work is sufficiently well known amongst the community at large; I reject their conclusions as has the community.


3. As I have said repeatedly, examples such as these have no relevance or analogy to QM. I have given you a simple challenge, one that involves not Bell but EPR. You see: EPR demonstrated that perfect correlations with entangled particles (systems that have interacted in the past) imply QM is incomplete or wrong. Well, back then there had never been an experiment with entanglement. And guess what, Remote Entanglement Swapping had never even been considered in anyone's wildest dreams. So the following challenge is simply a moderns re-creation of EPR. Hopefully this challenge will show any doubters the importance of the experimental results of the past 35 years.

There is a card player named Alice in Lille, and another named Bob in Lyon. Their card decks are completely uncorrelated. They can shuffle or even arrange their decks as they like, as long as there has been no communication or pre-arranged agreement between them. Then a magician named Chris in distant Paris snaps her fingers, and instantly: the Lille and Lyon card decks are perfectly correlated to the following standard. Dale, an observer in Versailles, selects a number from 1 to 52 as N. He phones Lille and Lyon and asks for the color of their Nth card in their respective decks. Amazingly, each of the decks produces the same color card for the Nth card. This trick is repeated as often as desired, with the same results. At no time is there any communication between the principals, other than Dale getting the results from Alice and Bob. How is this trick performed without breaking the rules?

This is the analogy that MUST be explained by anyone pretending there is local realism. This is NOT reproducing Bell, and has no assumptions regarding any of the red herrings presented by hand waving Bell Deniers respected scientific authors/teams with alternative opinions. This is simply reproducing the 1935 EPR elements of reality in 2024 form. "If, without in any way disturbing a system, we can predict with certainty (i.e., with probability equal to unity) the value of a physical quantity, then there exists an element of physical reality corresponding lo this physical quantity " With Remote Entanglement Swapping from Independent Sources, the elements of reality have never been in a common backward light cone.

Care to explain this modern version using specifics? This is as simple as it gets before eventalking about Bell. You start with completely uncorrelated photons, and end up with completely correlated photons. I've already referenced multiple experimental papers by Zeilinger teams and others, let me know if you need those.


4. As mentioned, Bell not involved.

 

[iste]

Remote Entanglement Swapping

This is not a big concern to me. Barandes' formulation can account for entanglement swapping. The relationship between generalized stochastic systems and quantum mechanics is bi-directional so you don't even have to construct a stochastic version of entanglement swapping experiments, you can just directly translate the quantum description into a stochastic one and it will retain the same behaviors but with trajectories of realized outcomes.

And Barandes' formulation is centered around violations for total probability for Markov properties. Violations of total probability signify breakdowns of joint probability distributions so the formulation seems to be amenable to the same kind of analysis of its own non-local phenomena in terms of Fine's theorem, absent joint probability distributions etc.

How is this trick performed without breaking the rules?

This is the analogy that MUST be explained by anyone pretending there is local realism.

Well presumably an example like this is assuming non-contextuality. From the perspective I have been arguing, and Fine's theorem, certain kinds of context-dependent statistics at each of the respective cities may be enough to preclude a joint probability distribution. Bell violations may just follow from that.

I think we just aren't going to agree because we have fundamentally different assumptions. You want a kind of explicit, detailed local-causal chain of events connecting the distant events; but from my perspective, this just doesn't exist. For me, it isn't necessary if you just look at the Bell violations as equivalent to joint probability violations - a formal relationship that just looks very, very strange and unintuitive but is not fundamentally about local chains of events, or indeed any kind of causal directionality. The equivalence seems well-established: e.g. another modern reaffirmation of Fine's theorem below.

https://arxiv.org/abs/1102.0264

"We show that contextuality, and non-locality as a special case, correspond exactly to obstructions to the existence of global sections [which defines a distribution on all measurement outcomes]."

Definite particle properties are then compatible with this if you allow an ensemble interpretation of the statistics and stochastic behavior in their trajectories.

So I don't understand the need for the kind of explanation you want when the presence of incompatible observables seems enough. Until one person changes their assumption then we just cannot agree, I guess.

 

[DrChinese]

1. Well presumably an example like this is assuming non-contextuality.

I think we just aren't going to agree because we have fundamentally different assumptions. You want a kind of explicit, detailed local-causal chain of events connecting the distant events; but from my perspective, this just doesn't exist.

2. Definite particle properties are then compatible with this if you allow an ensemble interpretation of the statistics and stochastic behavior in their trajectories.

So I don't understand the need for the kind of explanation you want when the presence of incompatible observables seems enough. Until one person changes their assumption then we just cannot agree, I guess.

1. Again, there are no assumptions at all, and certainly nothing whatsoever about contextuality (or not). It is simply a prediction of QM that any interpretation must to explain. This is 1935 thinking, pre-Bell, just nonlocal EPR "elements of reality" that are demonstrated experimentally by modern experiments with independent and distant sources.

There is no "detailed local-causal chain of events connecting the distant events; but from my perspective, this just doesn't exist" because... there IS quantum nonlocality. Not sure why you keep saying there are "local interactions" without saying there are nonlocal influences. Either there is nonlocality in Barandes' ideas (and yours) - or there is not. Which?

2. There are no ensemble statistics or "incompatible observables" here. Perfect correlations from distant systems that have never interacted eliminate all that.

While I don't agree we have different assumptions, I do agree that you refuse to address this simple challenge - that is already demonstrated experimentally as I have indicated.

Penn and Teller can wave their hands and magic happens, but this is actual science. How do those previously uncorrelated and distant decks of cards become correlated without a nonlocal influence? Anyone?

 

[martinbn]

How do those previously uncorrelated and distant decks of cards become correlated without a nonlocal influence? Anyone?

I don't think your challenge is fair. What you describe cannot be done with QM either.

 

[Fra]

Before I say anyone I am sensing again the old confusion what nonlocality means. We know that what Bell means, it's essentially the violation of the inequality; this KIND of "nonlocality" is of course not a problem per see and does not imply FTL-violations.

1. Again, there are no assumptions at all, and certainly nothing whatsoever about contextuality (or not). It is simply a prediction of QM that any interpretation must to explain. This is 1935 thinking, pre-Bell, just nonlocal EPR "elements of reality" that are demonstrated experimentally by modern experiments with independent and distant sources.

There is no "detailed local-causal chain of events connecting the distant events; but from my perspective, this just doesn't exist" because... there IS quantum nonlocality. Not sure why you keep saying there are "local interactions" without saying there are nonlocal influences. Either there is nonlocality in Barandes' ideas (and yours) - or there is not. Which?

2. There are no ensemble statistics or "incompatible observables" here. Perfect correlations from distant systems that have never interacted eliminate all that.

While I don't agree we have different assumptions, I do agree that you refuse to address this simple challenge - that is already demonstrated experimentally as I have indicated.

Penn and Teller can wave their hands and magic happens, but this is actual science. How do those previously uncorrelated and distant decks of cards become correlated without a nonlocal influence? Anyone?

My personal take on the "remote entanglement swapping" that you often hightlight is that it is just a combination of two independently correlated systems/pairs, that are post-filtered (the SWAP) thereby you achieve the entanglement between two partifcles that "never communicated". But this was debated in other threads, and I lost interest in the details, but I think you never got convinced to see it like this. Without the information from the SWAP even, you can never conclude the entanglement.

For me there core mystery in entanglement swapping is that same as in original entanglement, it's just a more complex example, that may rather obscure than clarify.

/Fredrik

 

[RUTA]

I don't think your challenge is fair. What you describe cannot be done with QM either.

Yes, more information than merely "snapping his fingers" is needed in order to produce an accurate analogy :-)

In quantum mechanics, the state providing the distribution of outcomes among the detectors contains information about the entire spatiotemporal context of the experiment given a particular source and its detectors (usually just implied, but necessary for understanding what the state is describing). I'm not talking about hidden variables, what I'm saying applies to the quantum state even if it is assumed to be complete. You have to know what the symbols in the mathematical representation of the state mean in terms of detectors for a source and their locations and/or orientations in space, so as to make physical sense of the distribution of outcomes for the experiment.

For example, the singlet state says when the detector settings are the same Alice and Bob will get opposite outcomes. So, you need to know what a detector and its settings are, what an outcome means for that detector, and you need a source that produces those outcomes for those detectors.

Anyway, we need all that information in the analogy so we can answer the challenge.

 

[Fra]

Anyway, we need all that information in the analogy so we can answer the challenge.

I think Dr Chinese meant that it's up to those that suggest that we can understand the logic of "quantum entanglement" outside of physics, such as in human interations - to complete the example. (Reasonable i admit!)

I think it may be possible but it takes some creativity to construct an example involving decks.

But I think an example must involve some kind of betting in an expectation game is required. I havent felt motivated to just that but i presume those researching game theory in relation to quantum strategies in economy might have some exsmpmes?

I googled and found this recent paper...

Bell correlations outside physics​

https://www.nature.com/articles/s41598-023-31441-x

/Fredrik

 

[DrChinese]

1. I don't think your challenge is fair. What you describe cannot be done with QM either.

2. Yes, more information than merely "snapping his fingers" is needed in order to produce an accurate analogy :-)

In quantum mechanics, the state providing the distribution of outcomes among the detectors contains information about the entire spatiotemporal context of the experiment given a particular source and its detectors (usually just implied, but necessary for understanding what the state is describing). I'm not talking about hidden variables, what I'm saying applies to the quantum state even if it is assumed to be complete.

3. My personal take on the "remote entanglement swapping" that you often hightlight is that it is just a combination of two independently correlated systems/pairs, that are post-filtered (the SWAP) thereby you achieve the entanglement between two partifcles that "never communicated".

1. It can be done and has been done. Here is the reference:

High-fidelity entanglement swapping with fully independent sources

Initially entangled Photons 1 and 2 (state ψ-) originate from the Slave, initially entangled Photons 3 and 4 (also state ψ-) originate from the Master. There is no initial correlation between Photons 1 and 4, which are created distant from each other (in terms of light speed). After a remote Bell State Measurement (BSM) on Photons 2 and 3, Photons 1 and 4 become perfectly correlated in one of 4 possible (and random) Bell states, only 2 of which can be identified (ψ+ or ψ-). The experiment only uses 4 fold relative coincidences within the specified time window, all others are ignored.

2. Sure, I simplified for example purposes. Although fleshing it out changes little for the challenge itself. And I agree with you statement about "entire spatiotemporal context of the experiment".

3. How do you post-filter something "here" and cause it to correlate something "there"? The final correlated pair has never been in the vicinity of each other, and are also separated from the swapping mechanism (BSM).

---

Original challenge: There is a card player named Alice in Lille, and another named Bob in Lyon. Their card decks are completely uncorrelated. They can shuffle or even arrange their decks as they like, as long as there has been no communication or pre-arranged agreement between them. Then a magician named Chris in distant Paris snaps her fingers, and instantly: the Lille and Lyon card decks are perfectly correlated to the following standard. Dale, an observer in Versailles, selects a number from 1 to 52 as N. He phones Lille and Lyon and asks for the color of their Nth card in their respective decks. Amazingly, each of the decks produces the same color card for the Nth card. This trick is repeated as often as desired, with the same results. At no time is there any communication between the principals, other than Dale getting the results from Alice and Bob. How is this trick performed without breaking the rules?

So to satisfy on some of the details of the analogy, let's clarify as follows:

1. In my original analogy: there were only 2 decks; but @RUTA wants more than a finger snap from the magician in Paris. So we'll need 4 decks to be more true to the referenced experiment. We'll label the card decks 1/2/3/4 to match the Photons in the experiment. Each set of 4 Decks represents a single 4 fold coincidence (i.e. one useful trial) in the experiment. Obviously, this is an analogy and every element of the actual experiment cannot be modeled.

2. To keep the explanation simple, we'll treat the initial entanglement (between 1 & 2, and between 3 & 4) as being state ψ+, meaning that there is initially correlation rather than anti-correlation. So Alice in Lille shuffles a Deck (Deck 1) and then created an identical one (Deck 2). Bob in Lyon does the same to end up with 2 identical decks, Deck 3 and 4. No communication or pre-agreement is allowed between Alice and Bob as to their Deck preparation. These are independently prepared, as in the actual experiment.

3. Alice sends her Deck 2 to magician Chris in Paris, and Bob sends his Deck 3 to Paris as well.

4. Here the analogy breaks down a little, as there is no classical manner to model the experimental Bell State Measurement producing ψ+ or ψ- outcomes. But we will allow as follows: The final correlated state of Decks 1 & 4 can be correlated ψ+ or anti-correlated ψ-, just as in the experiment. The magician's snap of the fingers will then be: the magician Chris will select a card randomly (no pre-arrangements allowed!) from each of the decks (Deck 2 from Lille, Deck 3 from Lyon). If the cards are the same color, then the Decks remaining in Lille and Lyon are correlated. If they are different colors, they are anti-correlated.

5. Dale, the observer in Versailles, need to get a call from Chris to learn whether Chris sees cards indicating Alice and Bob's decks (1 and 4) are correlated, or anti-correlated. So in the end: Dale picks N (from 1 to 52), Alice and Bob check their respective Nth cards and phone those results to Dale, and Dale already knows whether they will be correlated or anti-correlated. So once Dale receives the call with the result (red or black) from Alice, Dale can predict with certainty the result Bob will report.

---

What's the point of all of this? We have now realized the original 1935 version of EPR elements of reality: "If, without in any way disturbing a system, we can predict with certainty (i.e., with probability equal to unity) the value of a physical quantity, then there exists an element of physical reality corresponding to this physical quantity." This result was anticipated pre-Bell based on general expectations on entanglement as known back then.

But we did so in our analogy (and in the realized referenced experiment) with an important twist they could never have envisioned: The random correlations/anti-correlations were created nonlocally, without any type of coordination or initial correlation of any type between Alice and Bob ("independent sources") - in distant cities in the analogy, but outside backward light cones in the experiment.

So, here we have no assumptions related to Bell at all. There is no assumption of contextuality or non-contextuality, nothing about counterfactuals, etc. Elements of reality are created remotely in systems that have never interacted (unlike in the original).

My question demand for any Interpretation denying any form of nonlocality is: Specifically, in terms of this card deck example: how are Bob's random outcomes able to be predicted with certainty when all of Alice's and Chris' actions are far away, too far away to be explained by influences at speeds of c or less?

Of course there is no problem if there exist FTL components within the interpretation; or if the interpretation makes provision for including the future context as part of the overall mechanism (as some "acausal" interpretations do). We don't understand how standard/minimal/Copenhagen/orthodox/textbook QM accounts for this, but the generally accepted explanation is that there is *something* called "quantum nonlocality" that fits the bill. Quantum nonlocality being, in the analogy, the magician Chris' finger snaps.

 

[iste]

Again, there are no assumptions at all, and certainly nothing whatsoever about contextuality (or not).

Alright, Yes I see. I guess I was implying that contextuality is all you need.

Not sure why you keep saying there are "local interactions" without saying there are nonlocal influences

I just think that non-local correlations do not need to be causal and therefore they do not need to be influences in a causal sense.

There are no ensemble statistics or "incompatible observables" here. Perfect correlations from distant systems that have never interacted eliminate all that.

Yes, I know there are no ensemble statistics in the example; it was just a little add-on that with these factors you can have definite particle properties. I don't think ensemble statistics don't prevent perfect correlations at all if Bell violations can be derived from the absence of joint probability distributions.

And incompatibility is responsible for Bell violations so I don't really understand how asking someone to solve some thought experiment without them says too much.

While I don't agree we have different assumptions, I do agree that you refuse to address this simple challenge - that is already demonstrated experimentally as I have indicated.

Because the challenge has been addressed by Fine's theorem probabilistically.

 

[martinbn]

@DrChinese what is the 52 analogus to? It seems that you want to match 52 cards here and 52 there for a given trial, but with photones there are no 52 values that you get for a given measurement.

 

[DrChinese]

@DrChinese what is the 52 analogus to? It seems that you want to match 52 cards here and 52 there for a given trial, but with photons there are no 52 values that you get for a given measurement.

It's an analogy, nothing magic about 52 per se other than the simple visual of a randomly arranged deck of cards. Half are red, half black, all mixed up. So the analogy with the color is like a photon's H> or V> polarization (or however you want to represent it - +/- or 1/-1 etc) at some angle setting to be measured by both Alice and Bob. And the 52? How many different angles are there in a full circle? Or in a quarter circle? Technically you could say: infinite. But for our purposes, 52 different angles yielding a binary result should suffice.

There is no way to arrange such a deck of cards so that it would reproduce the usual cos^2(theta) statistics, any more than you could pre-assign values for 52 different polarization measurement outcomes on a photon. But we don't need that to hold, as we are looking only for the EPR perfect correlations ("elements of reality").

I just think that non-local correlations do not need to be causal and therefore they do not need to be influences in a causal sense.

Who said anything about causal influences? The outcomes are random as far as anyone knows. Certainly not a requirement of the challenge for some A to cause B, anyway you can make it work if it gets the necessary result. But "something" must be influencing "something", whether it is mutual, directionless, or displays a preferred direction in time.

This is experimentally demonstrated, proving the elements of reality appear. People hate the terms "action at a distance" and "FTL", so "quantum nonlocality" it is.

 

[martinbn]

But you cannot measure one photon at 52 angles. You can do it for just one angle. And QM, at least standard text book QM, says that the observables for the different angles do not commute. You cannot have values for all of them like a deck of cards. The better analogy would be to fix the axis and have just one card per person. If you need more angles you need more trials.

 

[RUTA]

@DrChinese, that's one convoluted experiment! But, it does beautifully portray the spatiotemporally global, "all-at-once" nature of the outcome distributions and correlations due to the original two Bell states and all the measurement locations and settings in spacetime. If the Bell states are complete, then there are no card decks, just a single card at each measurement outcome. In that case, you can imagine choosing a setting for each measurement then placing a card at each measurement outcome so that all the outcomes are consistent with the Bell states and measurement settings used. Of course in doing so, you're operating 'outside' spacetime, so good luck telling that story via causal mechanisms within spacetime :-)

 

[DrChinese]

@DrChinese, that's one convoluted experiment! But, it does beautifully portray the spatiotemporally global, "all-at-once" nature of the outcome distributions and correlations due to the original two Bell states and all the measurement locations and settings in spacetime. If the Bell states are complete, then there are no card decks, just a single card at each measurement outcome. In that case, you can imagine choosing a setting for each measurement then placing a card at each measurement outcome so that all the outcomes are consistent with the Bell states and measurement settings used. Of course in doing so, you're operating 'outside' spacetime, so good luck telling that story via causal mechanisms within spacetime :-)

But you cannot measure one photon at 52 angles. You can do it for just one angle. And QM, at least standard text book QM, says that the observables for the different angles do not commute. You cannot have values for all of them like a deck of cards. The better analogy would be to fix the axis and have just one card per person. If you need more angles you need more trials.

Agreed completely for both of you, didn't mean to imply that the cards not selected must have specific values (although I see why that comes across). EPR explicitly admits that only one "element of reality" can be demonstrated at a time. They also say in a local hidden variable scenario (a more complete specification of the system) all counterfactual possibilities would be assumed to exist. Whether they do or don't, that's part of the challenge: your trick must still explain how to get perfect correlations.

So there is to be just one angle setting (the Nth card) selected and tested per trial. There is no assumption here other than Alice and Bob can produce a result for that one common setting - no other cards need be looked at. To match experiment, Alice and Bob must get matching colors each trial. But they don't know which card (angle) will be selected in advance (unless there is a mechanism that allows this)! Yes, I know that there are 52 cards in my deck example, but that's merely an artifact of trying to map a quantum example into something we can picture mentally. That being that there is a choice of many measurement bases, whether it be 52 (corresponding to a card deck), 360 (corresponding to number of degrees in a circle), or 8 (the number of pieces in my apple pie).

---

@RUTA It seems convoluted because I cannot express myself more concisely, sorry 'bout that. The whole thing about cities in France (Lille, Lyon, etc) stretches back to the Doctor/Patient analogy using those cities - which is a terrible analogy because it does not relate in any relevant way to quantum mechanical experiments. This example is built around perfect correlations a la EPR.

So this really is exactly as described in 1935 EPR with these 2 differences: a) we are looking at a spin basis* rather than the position/momentum basis; b) most important: the 2 systems have never interacted, nor is there sufficient time for any 3rd signal to be transmitted to them both (once they are entangled) indicating how they are to be measured (or how to otherwise synchronize).

For someone who holds the viewpoint of Relational BlockWorld (RBW): This challenge is successfully met, because the mechanism of RBW ("the trick") would include as relevant elements the full quantum context, including the future elements. Being "acausal", there is no issue connecting the dots between seemingly distant points in spacetime, even from future to past. Because those spacetime points will actually all be connected by "acausal lines of influence" (not sure what you might call them) that all respect c. Exactly as the experiment is constructed using photons, which of course move at c anyway. I would call this "local" but not "locally causal" **. And I would call it fully contextual, because there are no counterfactuals to consider.

So for anyone asking about a good example of an interpretation that is local and non-realistic (i.e. explicit contextuality, and no hidden variables): here it is!


*This change was introduced around the time of Bohm (circa 1950).

** "Causal" meaning here: a) Causes are distinguished from effects; and b) causes must precede effects. "Acausal" or "not causal" denying one or both of a) and b).

 

[martinbn]

@DrChinese I still don't understand the challenge. Alice shuffles a deck and creates an identical one. Bob does the same completely independently. They send one of their decks to Chris. He picks out a number, say 10, looks at the 10th card of each deck. Their colour may match or not. If they do, we check cards number 10 in the decks at Alice's and Bob's. They match of course. But this is trivial and classical. QM can do a lot more than that. Of course I realize that this is not what you meant by your challenge, this isn't a challenge at all. So what did you mean?

 

[Fra]

It is trivial becase we explained the correlation but haven't specified a interaction at say Alice which involves her deck. To just "look at the deck" is trivial, it's hard to get some interferences out of that.

I think the challenge is find an "interaction" involving the deck states that we can understand (maybe via via some rationally randomly betting IGUS/agent) and that shows outcomes that differs depending on wether the entangled decks sent to Chris are kept SECRET(=isolated) or not, from the gaming enviromment, and other "players" in the implicit environment.

My hunch is I think such an example should be possible, but I don't have one. If we find on, that may convince Dr Chinese to take the analogies to "social interactions" and other context where claims to demonstrated bell inequality more serioulsy. One problem with that however, is that do make such an example we need to construct the correspondence of the "hamiltonian" for such agent interactions. And I fear those who do not like this could still object that these constructiions are ambigous, as such hamiltionians would necessarily be only "effective" as one can not make a first principle modelling of two interacting agents as it would be a chaotical dynamical system.

/Fredrik

 

[DrChinese]

@DrChinese I still don't understand the challenge. Alice shuffles a deck and creates an identical one. Bob does the same completely independently. They send one of their decks to Chris. He picks out a number, say 10, looks at the 10th card of each deck. Their colour may match or not. If they do, we check cards number 10 in the decks at Alice's and Bob's. They match of course. But this is trivial and classical. QM can do a lot more than that. Of course I realize that this is not what you meant by your challenge, this isn't a challenge at all. So what did you mean?

No, Chris does a different thing with the copy decks 2 & 3, simply picking a card from each deck - this is supposed to be the analog of performing a Bell State Measurement (BSM). That is a separate action and is not directly correlated to the polarization of the Alice & Bell angle settings. It is indirectly related because it indicates whether Alice and Bob's Nth cards is going to be perfectly correlated or anti-correlated. What I had said about this was:

"The magician's snap of the fingers will then be: the magician Chris will select a card randomly (no pre-arrangements allowed!) from each of the decks (Deck 2 from Lille, Deck 3 from Lyon). If the cards are the same color, then the Decks remaining in Lille and Lyon are correlated. If they are different colors, they are anti-correlated. ... Dale, the observer in Versailles, need to get a call from Chris to learn whether Chris sees cards indicating Alice and Bob's decks (1 and 4) are correlated, or anti-correlated. So in the end: Dale picks N (from 1 to 52), Alice and Bob check their respective Nth cards and phone those results to Dale, and Dale already knows whether they will be correlated or anti-correlated. So once Dale receives the call with the result (red or black) from Alice, Dale can predict with certainty the result Bob will report."

What we are trying to show if the practical difficulties of hypothesizing a local mechanism that has nonlocal appearance in the Remote Entanglement Swapping scenario. I don't think any local causal mechanism can accomplish this. Where local means: influences (random or not) not to exceed c; and causal means: the identified cause must precede an identified effect.

1. It is trivial because we explained the correlation but haven't specified a interaction at say Alice which involves her deck.

2. I think the challenge is find an "interaction" involving the deck states that we can understand (maybe via via some rationally randomly betting IGUS/agent) and that shows outcomes that differs depending on wether the entangled decks sent to Chris are kept SECRET(=isolated) or not, from the gaming enviromment, and other "players" in the implicit environment.

My hunch is I think such an example should be possible, but I don't have one. If we find on, that may convince Dr Chinese to take the analogies to "social interactions" and other context where claims to demonstrated bell inequality more serioulsy.

1. See above, there is no trivial explanation. I just didn't explain well. The 1 and 4 decks are initially uncorrelated, therefore the Nth card in each of these decks will not be perfectly correlated in Lille and Lyon. Chris does something in Paris and then they are correlated (anticorrelated) for the Nth card, regardless of the selection of N.

2. In actual experiments, the deck copies sent to "Paris" have a Bell State Measurement performed on them. That creates an entangled state for Decks 1 & 4 (Photons 1 & 4). The BSM (on 2 & 3) does not reveal any information about the color of the card (polarization) for the Nth card (angle setting) for 1 & 4. Chris in Paris doesn't even know what N is. To that extent, I guess you could say there is a "secret".

3. Again, the original deRaedt et al "Doctors in Lille and Lyon" social example (I am long familiar with that) in no way represents an analogy to quantum mechanics. The only purpose of that contrived example is to show that a "Bell-like" classical limit can appear to be violated in a specific classical scenario. This isn't a debate about whether such an example is a disproof of some underlying assumption in Bell (which it isn't). Here, nowhere are we referencing Bell inequalities!

Instead, Bell built on EPR's perfect correlations. Many an anti-Bell idea has been tripped up by forgetting that perfect correlations are a requirement too, as well as explaining violation of Bell inequalities. But one thing none of EPR or Bell lived long enough to learn of the existence of remote swapping (teleportation first proposed circa 1993, Rosen died 1995). Had they lived to see these Report Entanglement Swapping experiments realized, they would have certainly realized that the original EPR concept ("elements of reality") would now require nonlocal influences to work out.

 

[martinbn]

No, Chris does a different thing with the copy decks 2 & 3, simply picking a card from each deck - this is supposed to be the analog of performing a Bell State Measurement (BSM). That is a separate action and is not directly correlated to the polarization of the Alice & Bell angle settings. It is indirectly related because it indicates whether Alice and Bob's Nth cards is going to be perfectly correlated or anti-correlated. What I had said about this was:

"The magician's snap of the fingers will then be: the magician Chris will select a card randomly (no pre-arrangements allowed!) from each of the decks (Deck 2 from Lille, Deck 3 from Lyon). If the cards are the same color, then the Decks remaining in Lille and Lyon are correlated. If they are different colors, they are anti-correlated. ... Dale, the observer in Versailles, need to get a call from Chris to learn whether Chris sees cards indicating Alice and Bob's decks (1 and 4) are correlated, or anti-correlated. So in the end: Dale picks N (from 1 to 52), Alice and Bob check their respective Nth cards and phone those results to Dale, and Dale already knows whether they will be correlated or anti-correlated. So once Dale receives the call with the result (red or black) from Alice, Dale can predict with certainty the result Bob will report."

What we are trying to show if the practical difficulties of hypothesizing a local mechanism that has nonlocal appearance in the Remote Entanglement Swapping scenario. I don't think any local causal mechanism can accomplish this. Where local means: influences (random or not) not to exceed c; and causal means: the identified cause must precede an identified effect.

1. See above, there is no trivial explanation. I just didn't explain well. The 1 and 4 decks are initially uncorrelated, therefore the Nth card in each of these decks will not be perfectly correlated in Lille and Lyon. Chris does something in Paris and then they are correlated (anticorrelated) for the Nth card, regardless of the selection of N.

2. In actual experiments, the deck copies sent to "Paris" have a Bell State Measurement performed on them. That creates an entangled state for Decks 1 & 4 (Photons 1 & 4). The BSM (on 2 & 3) does not reveal any information about the color of the card (polarization) for the Nth card (angle setting) for 1 & 4. Chris in Paris doesn't even know what N is. To that extent, I guess you could say there is a "secret".

3. Again, the original deRaedt et al "Doctors in Lille and Lyon" social example (I am long familiar with that) in no way represents an analogy to quantum mechanics. The only purpose of that contrived example is to show that a "Bell-like" classical limit can appear to be violated in a specific classical scenario. This isn't a debate about whether such an example is a disproof of some underlying assumption in Bell (which it isn't). Here, nowhere are we referencing Bell inequalities!

Instead, Bell built on EPR's perfect correlations. Many an anti-Bell idea has been tripped up by forgetting that perfect correlations are a requirement too, as well as explaining violation of Bell inequalities. But one thing none of EPR or Bell lived long enough to learn of the existence of remote swapping (teleportation first proposed circa 1993, Rosen died 1995). Had they lived to see these Report Entanglement Swapping experiments realized, they would have certainly realized that the original EPR concept ("elements of reality") would now require nonlocal influences to work out.

But i already objected to this and you agreed! The 52 cards represent 52 angles of measurment. On a given trial with photons 1, 2, 3 and 4 you can measure only for one angle for wach photon, not 52. You are asking for the two decks, 1 and 4, to become correlated, all 52 cards. There is nothing like that in the entaglement swaping case.

 

[DrChinese]

But i already objected to this and you agreed! The 52 cards represent 52 angles of measurment. On a given trial with photons 1, 2, 3 and 4 you can measure only for one angle for wach photon, not 52. You are asking for the two decks, 1 and 4, to become correlated, all 52 cards. There is nothing like that in the entaglement swaping case.

I agreed that there is no assumption that the entire decks must be correlated. Just the one 1 & 4 pair being tested (the Nth card), which were not previously correlated. But they must be correlated for each and every trial. How is the trick accomplished?

The issue here is that with EPR: They specified there was correlation because the system had previously interacted. While the details of the interaction itself were not known, presumably there was some conservation rule or other mechanism at work. But with the new "updated" version of EPR: There was no interaction. So what trick causes the swap to correlate distant systems if they have never interacted?

Obviously, this nonlocal twist could never have been foreseen by Einstein, Bohr, or even Bohm or Bell. They all passed away prior to the discovery of nonlocal swapping.

 

[martinbn]

I agreed that there is no assumption that the entire decks must be correlated. Just the one 1 & 4 pair being tested (the Nth card), which were not previously correlated. But they must be correlated for each and every trial. How is the trick accomplished?

But this is classical! He picks the Nth cards from decks 2 and 3. If they match, which they will with 50% chance, the Nth cards of deck 1 and 4 will too. This is trivial. And happens on every trial.

The issue here is that with EPR: They specified there was correlation because the system had previously interacted. While the details of the interaction itself were not known, presumably there was some conservation rule or other mechanism at work. But with the new "updated" version of EPR: There was no interaction. So what trick causes the swap to correlate distant systems if they have never interacted?

Well i explained it. There is nothing magical with the cards. There is something quite different with entangelment, but entanglement swapping doesn't add anithing new to it.

Obviously, this nonlocal twist could never have been foreseen by Einstein, Bohr, or even Bohm or Bell. They all passed away prior to the discovery of nonlocal swapping.

I am not familiar with the history and when it was all realized first, but that doesn't matter for this discussion.

 

[DrChinese]

But this is classical! He picks the Nth cards from decks 2 and 3. If they match, which they will with 50% chance, the Nth cards of deck 1 and 4 will too. This is trivial. And happens on every trial.

I’ll repeat: Chris in Paris is performing the card trick equivalent of a swap. She has no idea what N is, that information is not communicated to Paris. There is thus no opportunity for Chris to look at the Nth cards in the first place. That’s why the trick cannot be accomplished as you imagine.

Instead, Chris picks one card randomly from each of the 2 decks and communicates “match” or “no match” as to color. This is as close to the swap analogy as we can get. In an actual Bell State Measurement, there is a measurement of polarization as one component of the overall BSM. But it is at an angle fully independent of the angle settings of Alice and Bob.

 

[martinbn]

I’ll repeat: Chris in Paris is performing the card trick equivalent of a swap. She has no idea what N is, that information is not communicated to Paris. There is thus no opportunity for Chris to look at the Nth cards in the first place. That’s why the trick cannot be accomplished as you imagine.

Instead, Chris picks one card randomly from each of the 2 decks and communicates “match” or “no match” as to color. This is as close to the swap analogy as we can get. In an actual Bell State Measurement, there is a measurement of polarization as one component of the overall BSM. But it is at an angle fully independent of the angle settings of Alice and Bob.

Ok, but then you need to look at the corresponding cards in 1 and 4. Say Chris picked the 5th card in 2 and the 10th card in 3. Then the 5th card in 1 and the 10th in 4 will be correlated.

If this is not what you mean then run the experiment with specific outcomes, so that I can see what the challenge is.

Now I suspect that your desired analogy is not analogous to the swap at all. Then the challenge is not fair. But I will wait to see the example of an experimental run to see what exactly you ask.

 

[DrChinese]

1. Ok, but then you need to look at the corresponding cards in 1 and 4. Say Chris picked the 5th card in 2 and the 10th card in 3. Then the 5th card in 1 and the 10th in 4 will be correlated.

2. If this is not what you mean then run the experiment with specific outcomes, so that I can see what the challenge is.

1. Chris has no communication from anyone about what N is, i.e. selecting the Nth card. That's because in a Bell State Measurement (BSM) on photons (card decks) 2 & 3, the angle settings are held constant and do not change from trial to trial. The information gained from the BSM indicates a ψ+ (colors of 2 & 3 match in the analogy) or ψ- (2 & 3 don't match in the analogy).

The real BSM actually operates like this, just so you can see that there is no useful information gained as to the specific outcomes that will be seen by Alice (photon 1) and Bob (photon 4):

a) The 2 & 3 photons must overlap in time (i.e. be indistinguishable) at a beam splitter (BS), and they can either come out the same ports or different ports of the BS. Whether you have ψ+ or ψ-: one will always be vertically polarized |V> and the other will always be horizontally polarized |H>. They are therefore always orthogonal, and in principle should never directly interact.

b) Each output port of the single BS has a polarizing beam splitter (PBS) and 2 detectors at their output ports - one for the |V> and one for the |H>. So 1 BS, 2 PBSs and 4 detectors in total for the BSM. The angle orientation of the 2 PBSs are the same, but bears no specific relationship to anything happening with Alice's and Bob's settings. Again, this is held fixed from trial to trial.

c) If both detectors click on one side (the same output port of the BS), the resulting Bell state is ψ+. If they show up on different sides of the BS, the resulting Bell state is ψ-. ψ+ means the Alice and Bob outcomes will correlate perfectly at any same angle setting selected for them. ψ- means the Alice and Bob outcomes will anti-correlate perfectly at any same angle setting. In other words: since the polarization outcomes of 2 & 3 are always |HV> or |VH> (indistinguishable), their polarization makes no difference to learning whether there will be correlation or anti-correlation for Alice and Bob. It is whether the 2 & 3 photons appear on the same side - or different sides - of the BS output ports that determines that.

Now, this entire BSM process cannot be mapped directly to any card decks. So I am merely modeling it as if Chris in Paris essentially picks 2 random cards and therefore gets a random outcome - which we then associate with ψ+ or ψ-. And a random outcome is precisely what the actual BSM produces!

2. Sure.

a) Alice (decks 1 & 2, these are to be alike) and Bob (decks 3 & 4, also to be alike) shuffle (or otherwise arrange) their decks independently.

b) They send decks 2 & 3 to Chris, who does "something" which produces a + or - result, without knowing anything about how Dale will select N (the Nth card from each of decks 1 & 4). Let's say Chris see different colors (Red from deck 2, Black from deck 3) and calls that a "-" (which would be ψ-). Note again, this is simply a random outcome of whatever Chris does, just like the outcome of a real BSM is random.

c) Chris sends her "-" result to Dale. Dale then selects N=37 (which neither Alice nor Bob knew in advance). He gets the color of Alice's 37th card. It is Red. Dale immediately know that Bob's 37th card will be Black, because Chris' "-" results means anti-correlated on Alice/Bob colors.

d) More trials might look like this:
Chris "+", Dale N=12, Alice=Red, Bob=Red (as Dale predicted).
Chris "+", Dale N=49, Alice=Black, Bob=Black (as Dale predicted).
Chris "-", Dale N=49, Alice=Black, Bob=Red (as Dale predicted).
Chris "+", Dale N=20, Alice=Black, Bob=Black (as Dale predicted).
Chris "-", Dale N=12, Alice=Red, Bob=Black (as Dale predicted).
Chris "-", Dale N=32, Alice=Black, Bob=Red (as Dale predicted).

How can Dale make good predictions when Alice in Lille and Bob in Lyon don't know what each other are doing; Chris does not know N (which is selected by remote Dale) and is merely reporting a random "+" or "-"?

---

Each of Dale's successful predictions are the EPR definition of an "element of reality". Alice's measurement could not have affected Bob's outcome if local causality holds - they are distant. In the original EPR, they believed that such an element of reality occurred because the Alice and Bob particles had interacted in the past, and there would be conservation rules at play. Therefore the result of any measurements on Alice and Bob must be predetermined (at least that's what their logic told them).

In my "modern" version of EPR: There is an element of reality in each trial, just as in the original. But... the Alice and Bob particles had NEVER interacted in the past. So there is no conservation rules at play to explain the observed correlation/anti-correlation. That is replaced by Chris' Bell State Measurement, which is the "cause" of the swap. Chris is too far away from all of the others for the outcome of Chris' BSM to affect the outcomes of Alice and Bob's measurement, if local causality* holds.

• Bohmian explanation: There is explicitly nonlocality, so locality** fails.
• Relational Blockworld ( @RUTA hopefully you agree here) : Reality is "acausal", so causality* fails.
• Orthodox QM: Quantum nonlocality mechanism is not specified in the theory, but locality** and/or causality* fails and the theoretical predictions are upheld.

*Causality meaning: there is a) an identifiable cause which is separate from its effect; and b) the cause must precede the effect.
** Locality meaning: no physical influence can propagate or otherwise connect space-like separated particles or events.

 

[martinbn]

@DrChinese It seems that you want what Chris does to be a projection of the 2 and 3 onto a Bell state. Everything else is irrelevant. The nonlocality and entanglement swap are not needed at all. Your challenge is simply to create a Bell state using cards. It is also inconsistant because 1&2 and 3&4 at the begining are not in Bell states.

 

[DrChinese]

@DrChinese 1. It seems that you want what Chris does to be a projection of the 2 and 3 onto a Bell state. Everything else is irrelevant. The nonlocality and entanglement swap are not needed at all. Your challenge is simply to create a Bell state using cards.

2. It is also inconsistent because 1&2 and 3&4 at the beginning are not in Bell states.

1. You cannot model a Bell State Measurement via card decks, as I have said repeatedly. It is purely quantum, and the actual process is not well understood anyway*. That is an essential step in actual experiments, and creates a piece of information needed to decode whether you have ψ+ or ψ- as the resulting Bell State for remote photons (cards) 1 & 4. So yes, it's completely relevant and necessary.

2. Of course they are. As originally stated: they start in a correlated Bell state, ψ+. From post #159 item #2:

To keep the explanation simple, we'll treat the initial entanglement (between 1 & 2, and between 3 & 4) as being state ψ+, meaning that there is initially correlation rather than anti-correlation. So Alice in Lille shuffles a Deck (Deck 1) and then created an identical one (Deck 2). Bob in Lyon does the same to end up with 2 identical decks, Deck 3 and 4. No communication or pre-agreement is allowed between Alice and Bob as to their Deck preparation. These are independently prepared, as in the actual experiment.

---

As I keep saying: If there's someone believing in local causality out there who can explain how remote scientists can perfectly entangle 1 & 4 (creating an EPR element of reality) by doing something called a BSM (remotely as well), here's your chance.


*The rules for executing the BSM are well enough understood, as seen by the various experimental implementations. But what in the heck is going on with "indistinguishability" of orthogonal photons that presumably cannot interact anyway? That is needed to create the ψ+ or ψ- Bell state. If they become distinguishable, there is no Bell state and thus no remote swap.

 

[martinbn]

1. You cannot model a Bell State Measurement via card decks, as I have said repeatedly. It is purely quantum, and the actual process is not well understood anyway*. That is an essential step in actual experiments, and creates a piece of information needed to decode whether you have ψ+ or ψ- as the resulting Bell State for remote photons (cards) 1 & 4. So yes, it's completely relevant and necessary.

2. Of course they are. As originally stated: they start in a correlated Bell state, ψ+. From post #159 item #2:

To keep the explanation simple, we'll treat the initial entanglement (between 1 & 2, and between 3 & 4) as being state ψ+, meaning that there is initially correlation rather than anti-correlation. So Alice in Lille shuffles a Deck (Deck 1) and then created an identical one (Deck 2). Bob in Lyon does the same to end up with 2 identical decks, Deck 3 and 4. No communication or pre-agreement is allowed between Alice and Bob as to their Deck preparation. These are independently prepared, as in the actual experiment.

---

In 1. You say that it is impossible to have a Bell state with cards. In 2. You say that they are entangled. Which one is it?

As I keep saying: If there's someone believing in local causality out there who can explain how remote scientists can perfectly entangle 1 & 4 (creating an EPR element of reality) by doing something called a BSM (remotely as well), here's your chance.

Just to be clear, i know that it is not possible. I am just critisizing your challenge.

*The rules for executing the BSM are well enough understood, as seen by the various experimental implementations. But what in the heck is going on with "indistinguishability" of orthogonal photons that presumably cannot interact anyway? That is needed to create the ψ+ or ψ- Bell state. If they become distinguishable, there is no Bell state and thus no remote swap.

 

[DrChinese]

In 1. You say that it is impossible to have a Bell state with cards. In 2. You say that they are entangled. Which one is it?

2. Just to be clear, i know that it is not possible. I am just critisizing your challenge.

1. It's impossible to model a Bell State Measurement (BSM) with cards. Bell states are different.

You can model an entangled deck with cards, at least for perfect EPR correlations. To model the ψ+ Bell state, you sort 2 decks into the same order. To model ψ- Bell state, you sort the 2nd deck with Black cards where there are Red cards in the first deck, and vice versa. (These won't model a Bell test an angles where there is an Inequality, but that isn't necessary for this challenge.)

2. Good, we agree.

As to the challenge: After all the hand-waving that goes on in various debates about Bell, apparently the basic EPR version cannot be explained either (with the newer entanglement swapping experiments). The challenge is correct, but I readily admit I may not have expressed myself particularly concisely. Again, I was attempting to show that the De Raedt et al example (the Doctors in France) itself was not a useful or reasonable model of quantum behavior. I say that mine is much closer, and certainly easier to visualize because there are perfect correlations.

 

[Fra]

3. How do you post-filter something "here" and cause it to correlate something "there"? The final correlated pair has never been in the vicinity of each other, and are also separated from the swapping mechanism (BSM).

The final correlated 1&4 pairs are not even defined until Chris has tagged the matches and communicated to Alice and Bob so they can "filter" the random pairs.

The fact that 1&4 has never been in contact, does not matter because it's not how the remotely entangled systems are constructed.

They are constructed from two independently entangled pairs, and whose mutual "correlation" is CREATED from "filtering" based on the tag info from Chris. This is pure information processing, this is why there is no non-nocal action needed. This filtering can be done at any point in time, which is why order does not matter. But what does matter is that that info from swap tagging at Chris, must be available, otherwise one can never identify the entangled remote pairs.

Of course to maintaing the the quantum mechanical entanglement of a macroscopic objects like two deck of cards, is practically impossible, but the propose analogy i had in mind (but hae no example) lies at another level. Instead of considering the "physical interaction" of the deck of cards with the physical environment, the "interaction" is more towards the "gaming environment" or the "market". So the "interaction" is not about the litteral "cards", it's about the information the cards represent and how it influences someone playing and betting with them. It is a different abstraction, and "isolation" here does not mean the same as the isolation done with photons or electron pairs. But nothign in this thread or example explicitly defines such an example. I think this is what i meant by suggesting that the card deck example is trivial; you can't demonstrate the quantum interference unless you define the "gaming interaciton" that I envision. Just looking at the cards alone seems insufficient.

/Fredrik

 

[Fra]

1. It's impossible to model a Bell State Measurement (BSM) with cards. Bell states are different.

Yes. At least if you think of the physical state of the cards. One probably needs the gaming context, to make the illustration. With photons and electronics the context is inteactions with the polarizer for example, but the corresponding interaction between the state of the deck, and a betting agent is not defined, this is why the analogy is hard to see I think. But conceptually the agents behaviour, is reflecting the ignorance of the deck.
That would not corresond to the physicists ignorance of a hidden variable(falsified by bell), but more the polarizers ignorance of the hidden variable and the polarizer is informed from interacting constantly with the macroscopic enviroment(this is the difference). And in QM as it stands we have not "definition" or formalism for such concepts, which is again why the analogy is hard to see, it is certainly not explicit.

/Fredrik

 

[DrChinese]

1. The final correlated 1&4 pairs are not even defined until Chris has tagged the matches and communicated to Alice and Bob so they can "filter" the random pairs.

The fact that 1&4 has never been in contact, does not matter because it's not how the remotely entangled systems are constructed.

They are constructed from two independently entangled pairs, and whose mutual "correlation" is CREATED from "filtering" based on the tag info from Chris. This is pure information processing, this is why there is no non-nocal action needed. This filtering can be done at any point in time, which is why order does not matter. But what does matter is that that info from swap tagging at Chris, must be available, otherwise one can never identify the entangled remote pairs [as being ψ+ or ψ-].

Sorry, the "filtering hypothesis" is theoretically and factually incorrect, and this has even been experimentally demonstrated as such.

First, all 2 & 3 pairs that fit within the time window of the BSM lead to entanglement of 1 & 4 into one of the 4 Bell states. There is no filtering happening; if there are 2 near-simultaneous clicks at the BSM, there is a swap.

There cannot be a hidden correlation between the 1 & 4 pairs waiting to be revealed, since they are independently prepared. It should be obvious that the 1 & 4 photons - from fully independent sources - yield random outcomes which cannot be independently sorted into buckets using a coding mechanism that does not exactly reveal the same information as Alice and Bob obtain in the first place. In other words: Chris would need to perform the same experiment on 2 & 3 as Alice and Bob do on 1 & 4 to obtain the information you imagine. That isn't being done by Chris. (And in fact there is some polarization information being obtained by the BSM; but since it is always either |HV> or |VH> it is itself useless.) And it wouldn't lead to entanglement of 1 & 4 if that's what Chris did. It would be classical (and couldn't even violate a Bell inequality, since there would be Product State statistics).

Besides, in many of the swapping experiments: the orientations that Alice and Bob are measuring are selected mid-flight. It is done too late for there to be any light speed communication between the various observation stations. See this important swapping experiment in which independent random number generators are used for the Alice and Bob observations.


Second: Were what you said true, then why does indistinguishability even matter? By your concept, all that Chris does with the Bell State Measurement (BSM) is reveal whether we have ψ+ or ψ-. You even say it is pure information processing. Well guess what, you can obtain that exact same information - i.e. the markers indicating ψ+ or ψ- - even without indistinguishability. But... no indistinguishability, no entanglement! The marker for ψ+ is simultaneous clicks on the |H> and |V> detectors by the same output port of the beam splitter portion of the BSM. The marker for ψ- is simultaneous clicks on the |H> and |V> detectors by different output ports of the beam splitter portion of that BSM.

This particular point was analyzed and tested in this swapping experiment. From the paper (and note that this particular experiment looks at the 2 φ Bell states instead of the 2 ψ Bell states):

"One can also choose to introduce distinguishability between the two projected photons. In this case, the phase between the two terms of the |φ> projected state is undefined, resulting in a mixture of |φ+> and |φ−> in the projected state, and the first and last photons do not become quantum entangled but classically correlated. We observed this when we introduced a sufficient temporal delay between the two projected photons (see Fig. 3c). It is also evidence that the first and last photons did not somehow share any entanglement before the projection of the middle photons."

If the BSM is just filtering - and there is no remote physical projection occurring - then this result should not occur.


Third: the "filtering hypothesis" implies that any 2 entangled photons arriving within the coincidence window of the BSM would have their entangled partners containing "hidden" correlations waiting to be revealed. There cannot be sunc hidden maximum entanglement - pre-existing and waiting to be revealed - between 3 photons without violating Monogamy rules. The BSM must be successful as a physical process to cause the entanglement swap.

---

To quote the earlier reference from the team of Kaltenbaek et al:

"A successful entanglement swapping procedure will result in photons 1 and 4 being entangled, although they never interacted with each other. ... We confirm successful entanglement swapping by testing the entanglement of the previously uncorrelated photons 1 and 4."

 

[lodbrok]

Sorry, the "filtering hypothesis" is theoretically and factually incorrect, and this has even been experimentally demonstrated as such.

Not sure where you get that idea from. The experimenters themselves state that filtering is happening.

in https://arxiv.org/ftp/arxiv/papers/1203/1203.4834.pdf
... What, however, is important is to relate the lists of Alice, Bob and Victor’s measurement results. On the basis of Victor’s measurement settings and results, Alice and Bob can group their earlier and locally totally random results into subsets which each have a different meaning and interpretation. This formation of subsets is independent of the temporal order of the measurements. ...

https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.80.3891
Experimental Entanglement Swapping: Entangling Photons That Never Interacted

To verify that this entangled state is obtained, we have to analyze the polarization correlations between photons 1 and 4 conditioned on coincidences between the detectors of the Bell-state analyzer.
...
If entanglement swapping happens, then the twofold coincidences between D1+ and D4, and between D1- and D4, conditioned on the |ψ⟩₂₃ detection, should show two sine curves as a function of Q which are 90± out of phase
...
In that case, one could consider Alice performing the Bell-state measurement on photons 2 and 3, telling Bob, who is in possession of photon 4, the result of the Bell-state measurement.

Experimental delayed-choice entanglement swapping
https://www.nature.com/articles/nphys2294

In our experiment, the primary events are the polarization measurements of photons 1 and 4 by Alice and Bob. They keep their data sets for future evaluation. Each of these data sets by itself and their correlations are completely random and show no structure whatsoever. The other two photons (photons 2 and 3) are delayed until after Alice’s and Bob’s measurements, and sent to Victor for measurement. His measurement then decides the context and determines the interpretation of Alice’s and Bob’s data.
...
According to Victor’s choice of measurement (that is, entangled or separable state) and his results (that is, |φ+〉23, |φ−〉23 or |H H〉23, |V V 〉23), Alice and Bob can sort their already recorded data into 4 subsets. They can now verify that when Victor projected his photons onto an entangled state (|φ+〉23 or |φ^− 〉23), each of their joint subsets behaves as if it consisted of entangled pairs of distant photons. When Victor projected his photons onto a separable state (|H H〉23 or |VV〉23), Alice’s and Bob’s joint subsets behave as if they consisted of separable pairs of photons. In neither case Alice’s and Bob’s photons have communicated or interacted in the past.

 

[DrChinese]

1. The experimenters themselves state that filtering is happening.

1. There are 2 subsets of 4 fold entangled coincidences that are relevant (all within the appropriate time window): ψ+ and ψ-. The only "filtering" is the requirement of 4 fold coincidences. Note that there are 4 Bell states, but only 2 of the 4 can be identified in most experiments. The other 2, that can't, don't result in 4 fold coincidences. If there is 3 fold coincidences (i.e. clicks at detectors 1 and 4, and just *one* at the Bell State Measurement/BSM): there is entanglement and there is a swap, but which of the other 2 Bell states occurred is unknown.

So the only "filtering" is the sorting into the ψ+ bucket and the ψ- bucket. It is true that most detections at the BSM are single detections (i.e. one click within the time window). I guess you could call that "filtering", but it is not as if those meet the BSM criteria.

---

2. Your reference for Zeilinger's group (Ma et al) said:
Experimental delayed-choice entanglement swapping
https://www.nature.com/articles/nphys2294 [This is the arxiv version, no paywall]

"In our experiment, the primary events are the polarization measurements of photons 1 and 4 by Alice and Bob. They keep their data sets for future evaluation. Each of these data sets by itself and their correlations are completely random and show no structure whatsoever. The other two photons (photons 2 and 3) are delayed until after Alice’s and Bob’s measurements, and sent to Victor for measurement. His measurement then decides the context and determines the interpretation of Alice’s and Bob’s data.
...
"According to Victor’s choice of measurement (that is, entangled or separable state) and his results (that is, |φ+〉23, |φ−〉23 or |H H〉23, |V V 〉23), Alice and Bob can sort their already recorded data into 4 subsets. They can now verify that when Victor projected his photons onto an entangled state (|φ+〉23 or |φ^− 〉23), each of their joint subsets behaves as if it consisted of entangled pairs of distant photons. When Victor projected his photons onto a separable state (|H H〉23 or |VV〉23), Alice’s and Bob’s joint subsets behave as if they consisted of separable pairs of photons. In neither case Alice’s and Bob’s photons have communicated or interacted in the past.


2. You are mixing analogy/wording here. This is the delayed choice version, just want to be clear . So in this version, we have 4 fold coincidences exactly as I described in 1. above. Alice and Bob receive their respective photons 1 & 4 before the BSM occurs (this doesn't matter for our purposes).

Yes, it is a true statement - as you highlight - that Alice and Bob's photons - when there is 4 fold coincidence - will form 2x2 subsets for each of 3 possible basis choices that are performed by Alice and Bob: |H>/|V>, |R>/|L>, |+>/|->. They match (correlate) or don't match (anti-correlate) based on whether the entangled state is φ+ or φ-. Or alternately fail to correlate on some bases when there is no swap (per Victor's choices).

These are then related to the following at the BSM, based on the choices made by Victor (see figure 3 at bottom of paper):

Victor allows entanglement swap (to Bell state φ+ or φ-):
H/V basis: Correlation indicating either entanglement or product (separable) state
R/L basis: Expected correlation indicating entanglement
+/- basis: Expected correlation indicating entanglement

Victor prevents entanglement swap (Product state):
H/V basis: Correlation indicating either entanglement or product (separable) state
R/L basis: No correlation, product state
+/- basis: No correlation, product state

In each scenario, since there are 4 fold coincidences/clicks (the stated criteria), the experimenters match the Alice/Bob data with the appropriate result at Victor's BSM and summarize their results. Which are: when swaps succeed, there is the expected correlation; when the swaps are prevented from occurring, the hallmarks of entanglement are not present.

---

Nothing tricky about any of this, normal stuff for any experiment. And none of this is important for explaining how local causal interpretations can explain the basic results. Which are: perfect correlations (as adjusted for Bell state φ+ or φ-). We know the perfectly correlated entangled state results for photons 1 and 4 would be exactly the same if:

a) The sources of the 2 photon pairs are far distant, so that photons 1 and 4 share no backward light cone;
b) The settings for Alice and Bob's measurements are changed mid-flight;
c) The choice of whether to entangle photons 1 and 4 is made after they are detected and recorded; and/or
d) The detection loophole is eliminated.

"Filtering" has nothing to do with any of this, and explains exactly: nothing. And none of this involves Bell's Theorem in any way, so any "hidden" assumptions in Bell are moot. I am asking: How do perfect Entangled State correlations appear for initially uncorrelated photons that have never shared a common past, based on a decision to execute a swap by a distant experimenter?

 

[lodbrok]

Filtering" has nothing to do with any of this, and explains exactly: nothing. And none of this involves Bell's Theorem in any way, so any "hidden" assumptions in Bell are moot. I am asking: How do perfect Entangled State correlations appear for initially uncorrelated photons that have never shared a common past, based on a decision to execute a swap by a distant experimenter?

Filtering plays a huge part as already explained. Until the BSM results are used to condition the 14 analysis, no 14 entanglement can be demonstrated. This is the absolutely necessary filtration step that answers all your questions. Your question at the end has been asked by you and answered many times by different participants here in multiple threads, sometimes in painful detail. Please could we not turn every thread into an argument about an aspect of entanglement swapping that's not even controversial in the literature?

The new interpretation tries to derive the QM equations starting from simpler axioms. That is, an indivisible non-markovian stochastic process. From this it derives all the components. In this sense it presents a different view about what the mathematical entities mean, that's why it is a new interpretation. It does not propose an ontology of what is really happening other than to clarify that the derived mathematical entities are not physically existing objects.

Therefore this discussion about entanglement swapping adds nothing to this thread in my humble opinion.

 

[DrChinese]

1. Filtering plays a huge part as already explained. Until the BSM results are used to condition the 14 analysis, no 14 entanglement can be demonstrated. This is the absolutely necessary filtration step that answers all your questions.

2. The new interpretation tries to derive the QM equations starting from simpler axioms. That is, an indivisible non-markovian stochastic process. From this it derives all the components. In this sense it presents a different view about what the mathematical entities mean, that's why it is a new interpretation. It does not propose an ontology of what is really happening other than to clarify that the derived mathematical entities are not physically existing objects.

3. Therefore this discussion about entanglement swapping adds nothing to this thread in my humble opinion.

1. Yes, it's true that the results of 3 distant observers must be brought together to demonstrate nonlocality. That would always be true in demonstrating quantum nonlocality*. So if that is your "out", it's circular reasoning. There is no meaningful filtering occurring, in the sense that some 4 fold events are ignored. And there is no reference to Bell's Theorem in these experiments to need to get around.


2. The entire point is that the perfect correlations between distant experiments outside of backward light cones cannot be explained by the interpretation which is the subject of this thread. "Not physically existing objects" (your words) as an out? That's it?? They are physically demonstrated effects. As with many interpretations which claim to explain Bell inequalities by redefining language, challenging Bell assumptions, etc., this one appears to claim that a series of local actions can lead to a nonlocal result. Well, how specifically? Big claims are cheap (quote below from his abstract), especially when non-Bell experiments (featuring perfect non-local correlations, as I presented) say otherwise. And it sure sound like new ontology to me, in fact a hidden variables approach (I deduced that from his claim about "hidden-variables").

"...this paper introduces a new principle of causal locality that is intended to improve on Bell's criteria, and shows directly that systems that remain at spacelike separation cannot exert causal influences on each other, according to that new principle. These results therefore lead to a general hidden-variables interpretation of quantum theory that is arguably compatible with causal locality."


3. I agree that I have had my say. Apparently you (as best I can tell) and some others dismiss the many important post-Bell developments in entanglement theory and experiment which invalidate virtually any interpretation holding on to local causality** (or Barandes' "causal locality"***, or almost any "local anything"). I have cited plenty of relevant research, and explained its relevance as a yardstick for new interpretations of QM. I doubt I can anything useful.


*Unless you could perform FTL signaling (which you can't of course)
**As for example described by Bell's 1975 paper. If only he were alive today to see how far things have progressed. "Zeilinger recalls when he met Bell at a conference in Amherst, in 1990, how enthusiastic Bell was about the [GHZ] result." from section 8.3 here. GHZ being another result demonstrating nonlocal "elements of reality" based on the actions of mutually distant experimenters.
***His changing the wording order from "local causality" to "causal locality" makes me . Like that changes everything...

 

[WernerQH]

It is unfortunate that Barandes' "interpretation" does not make explicit what quantum theory is about. A stochastic theory could be a significant improvement over a statistical theory purportedly describing the properties of quantum "particles". It is misleading to think of photons as objects with "properties" (like vertical, diagonal, or circular polarization), because according to the theory those may be completely undefined, and are just as well properties of the detectors, which can detect only particular kinds of polarization. In a recent thread there wasn't even consensus on the conditions under which photons can be called "entangled".

 

[Fra]

I planned to comment more detail but lodbrok responded well on the filtering part so no need to rephrase that. So I will shorten my comments, and focus on what I think the key points and the focus of the thread?

Sorry, the "filtering hypothesis" is theoretically and factually incorrect, and this has even been experimentally demonstrated as such.

First, all 2 & 3 pairs that fit within the time window of the BSM lead to entanglement of 1 & 4 into one of the 4 Bell states. There is no filtering happening; if there are 2 near-simultaneous clicks at the BSM, there is a swap.

As already said in the thread, the full unfiltered data at Alice/1 & Bob/4 is not correlated - unless gated/filtered using mandatory information classically sent from the BSM results. This is the "filtering" I refer to and that is in place.

But I think this is not really what you object to! You just seem to object due to tweaking of wordings, because you seek to UNDERSTAND HOW the correlation is possible (*), if there are no "hidden keys" that is a local causal explanation, that are created during pair production and swapped during swapping?

Do you find that the filtering explanation sort of hints that some kind of hidden key is there but at the same time, you conclude that (in line with assumptions in bells theorem) this can not be right! Thus the explanation must be something else - some nonlocal influence? And this is why you keep objecting to explanations that you feel is in contradiction to bells theorem?

Before I go on to associate to Barande: is this a fair assessment of your perspective or did I miss something else?

(*) And Barandes paper does not explain this in detail.

/Fredrik

 

[Fra]

And there is no reference to Bell's Theorem in these experiments to need to get around.

This is the point.

My view, and I think that is one Barandes keys as well is that the ansatz of Bell simply does not apply to the general case. Barandes puts is so that markov divisibility is wrong in the general case - and them specificially in the case of quantum interactions.

The difficulty is to conceptually understand or motivate this. Barande claims that the assumption does not follow from the general inference rules, and I think this is correct. Bells ansatz is indeed following from classical intuition of "ignorance of the observer". But just becase no such hidden variable model is allowed, does not mean that more general hidden variable models are not, right?

As with many interpretations which claim to explain Bell inequalities by redefining language, challenging Bell assumptions, etc., this one appears to claim that a series of local actions can lead to a nonlocal result. Well, how specifically? Big claims are cheap (quote below from his abstract), especially when non-Bell experiments (featuring perfect non-local correlations, as I presented) say otherwise. And it sure sound like new ontology to me, in fact a hidden variables approach (I deduced that from his claim about "hidden-variables").

I agree this criticism is fair as coming from an opposing perspective. This is exactly what I meant in my first post in the thread.

/Fredrik

 

[Fra]

3. I agree that I have had my say. Apparently you (as best I can tell) and some others dismiss the many important post-Bell developments in entanglement theory and experiment which invalidate virtually any interpretation holding on to local causality** (or Barandes' "causal locality"***, or almost any "local anything"). I have cited plenty of relevant research, and explained its relevance as a yardstick for new interpretations of QM. I doubt I can anything useful.

Given that Barande rejects the markov divisibility (which is the KEY problem in Bell ansatz that is essentially the same as the "physicists ignorance" assumption) then we do NOT have kind of causality that bells theorem applies to, so it's fair to give it a new name. I think it's not just a renaming of the same thing.

So I think noone dismiss bell theorem, nor claim bell was wrong. It's just that not ALL theories that entertain some sort of HV or stochastics to them are of the bell type, and then the theorem does not apply. What is wrong about that?

A problem of the meaning of locality and causation if one is thinking in terms of 3D space + time, or wether than is thinking in terms of an information processing scheme, where 3D is likely ultimately emergent anyway.

Anyone that wants to defend the markov divisibility assumption? It surely applies to a ignorant physicists, but when else? In game theoretic analogy, the ignorant physicists would be like an ignorant "judge", but the alternative is there even the players are ignorant; then their information becomes part of the game, and such simple partitions into hidden keys does not work.

/Fredrik

 

[DrChinese]

1. As already said in the thread, the full unfiltered data at Alice/1 & Bob/4 is not correlated - unless gated/filtered using mandatory information classically sent from the BSM results. This is the "filtering" I refer to and that is in place.

2. ...you seek to UNDERSTAND HOW the correlation is possible (*)... Thus the explanation must be something else - some nonlocal influence? And this is why you keep objecting to explanations that you feel is in contradiction to bells theorem?

3. Given that Barande rejects the markov divisibility (which is the KEY problem in Bell ansatz that is essentially the same as the "physicists ignorance" assumption) then we do NOT have kind of causality that bells theorem applies to

1. Agree, that's true in all swapping setups. The experiment consists of having another distant scientist who makes a decision to entangle - or not - the 1 & 4 photons. Of course, she must his report her results just as Alice and Bob do. I wouldn't call requiring the results of distant observers being brought together for analysis "filtering", when the purpose is to demonstrate quantum nonlocality in the first place.


2. It (the entanglement/correlation) is through a quantum nonlocal mechanism, the nature of which I have no clue except what is learned from experiments and standard theory. What I am asking is for those who come up with new interpretations to explain these experiments. Yes, I of course agree with the usual results of Bell's Theorem - and I disagree with attempts by some interpretations to evade Bell.

This is why I am reverting back to experiments that do not require a Bell-like approach - because those can't be evaded by the same hand-waving. Entanglement swapping and GHZ being 2 alternate approaches that demonstrate nonlocal "elements of reality" (by Einstein's definition). No probability involved, a certain prediction of distant outcomes based on the decisions of remote observers. (Einstein would have been surprised at these experiments, as they directly demonstrate the remote steering of reality using the same basic quantum mechanical theory he was familiar with - which he thought must be incomplete.)


3. I have never (in hundreds of papers on the subject) seen "Markov divisibility" seen as relating in any manner whatsoever to Bell. Where did Bell touch on anything close to that in his 1964 paper?

If someone has a different-than-Bell usage of "locality" and/or "causality", considers that an "out" from the Bell conclusion, and then decide that explains QM via local hidden variables... well, I'm not trying to debate that either way here.

 

[Fra]

3. I have never (in hundreds of papers on the subject) seen "Markov divisibility" seen as relating in any manner whatsoever to Bell. Where did Bell touch on anything close to that in his 1964 paper?

That term, is from Barandes... You are right of course Bell did not use that term, neither do I, but however we label it, it is IMO one of two key assumptions going into Bell's ansatz. I mean this ansatz in Bells's paper

-- https://cds.cern.ch/record/111654/files/vol1p195-200_001.pdf

IMO, if you elavorate Bells expression involving conditional probabilities it contains TWO assumptions,
1) statistical independence of A and B (this is fine)
2) What I've called the equipartition assumption in terms of the hidden variable, in the lack of better world, but Baranders calls it "Markov divisibility". (this is not so fine)

-- Jacob Barandes - "A New Formulation of Quantum Theory"

I think both these assumptions are FINE in the original context however, and in the context of looking for an actual classical "ignorance interpretation" which would suggest QM beeing incomplete. But from my and apparently others, interpretational stance, this is far from obvious. In particular, in the agent interpretations, I personally find this assumption is not even plausible. (This is my personal opinon, and why i highlight this, as I am happy to see others point the finger on the exact same spot, but perhaps from a different angle because I admit I do not see Barandes "big plans" if they exist).

/Fredrik

 

[iste]

From this it derives all the components. In this sense it presents a different view about what the mathematical entities mean, that's why it is a new interpretation. It does not propose an ontology of what is really happening other than to clarify that the derived mathematical entities are not physically existing objects.

It is unfortunate that Barandes' "interpretation" does not make explicit what quantum theory is about.

...

Well apart from suggesting that much of the quantum objects are not physical objects, it also gives actual, definite outcomes at every moment in time. It does this without needing to add anything new since the core of the formulation is just to show that quantum systems are equivalent to certain kinds of stochastic ones. But yes, apart from that, it doesn't actually say exactly how or why the stochastic system produces quantum phenomena beyond his assumptions about the structure of a generalized stochastic system characterized by a "linear marginalization condition" and non-markovianity. But from an online presentation he gave on it, he views this formulation as giving a kind of "physical picture" of quantum mechanics.

Looking at the last Barandes paper specifically on locality a little more closely, I think maybe his criteria for locality here is maybe a bit weak imo; and at face value, actually I am not entirely sure entanglement swapping would strictly meet the criteria set for locality at the end of the paper so I guess Mr. Chinese has a point there.

That said, I still like the view that these quantum non-local correlations don't necessarily need to be more than a very unintuitive statistical effect. I mean, it's interesting that you can have what seem like relatively minimal assumptions of a non-Markovian stochastic system and get non-local correlations without needing to specify further underlying mechanisms. The non-markovianity seems to be the big part of what matters; and even though I imagine what Mr. Barandes has presented so far probably doesn't have perfect non-local correlations like Mr. Chinese talks about, it still seems pretty explanatorily significant that you can get these illicit non-local correlations in a manner that looks just like a generic quantum entanglement from a kind of basic stochastic system.

As I have said before, the non-markovianity condition looks just like the kind of violation of total probability which you get for incompatible observables and at the center of contextual phenomena and Bell/Boole violations. It relates to interference terms in same way as total probability violations do in standard quantum mechanics. Specifically the condition would correspond to total probability violations for the trajectories in the path integral formulation (square of sums is not sum of squares); the definite outcomes in this formulation then correspond to actual realizations of the paths which naturally should then sample all possible trajectories if you keep repeating an experimental scenario indefinitely. Could you also get the perfect Bell correlations of quantum mechanics through this formulation? Presumably, if Mr. Barandes' formulation is sound then you should be able to just express those Bell scenarios, or at least maybe ones that are sufficiently analogous, in terms of generalized stochastic systems by using Mr. Barandes' dictionary; he does say in one paper you can build spin into the model. If strange interference as a consequence of phase shows up then presumably the perfect correlations should also show up too under some particular construction of a stochastic system... if the quantum constructs required to produce the Bell correlations can be, effectively, translated into stochastic form? Obviously we haven't seen this yet - I guess its an open question, the state of this formulation further on down the road. But since this formulation is just about the bi-directional "dictionary" translation between quantum and stochastic systems then what I have said should be the case if Barandes' formulation is sound... right?

I think it is not about getting rid of non-local correlations, but making them non-spooky. Unintuitive consequences of non-commutativity, implemented through local entangling interactions, local measurement interactions. The attraction of this kind of formulation maybe is that, just like some might give the challenge of "How do you produce this strange correlation in this scenario?", I can see someone giving the challenge of asking how/why would you inject strange ontologies into it? Because my impressions is it naturally gives weird quantum behaviors from a very sparse, unextravagant kind of foundation (there is no physical collapse either - it appears in the formulation purely as statistical conditioning). It makes it look like strange quantum phenomena don't need to be explained by some novel metaphysics (apart from natural stochastic behavior) but as very unintuitive consequences that just seem to emerge from certain kinds of statistical structures because the kind of constraints you would normally expect have been lifted. I think maybe I can see why Barandes' is pushing for this to be seen as a "causally locally" hidden variable model; it looks nominally local because the components are so unextravagant until you inspect the behavior in certain situations. Maybe quantum mechanics is generally like that but the quantum formalism makes it seem much more mysterious and open to interpretation compared to formulating it as just stochastic processes. The need for excessively novel metaphysics then seems deflated.

 

[WernerQH]

Well apart from suggesting that much of the quantum objects are not physical objects, it also gives actual, definite outcomes at every moment in time.

Does it? This needs to be substantiated. What "definite outcomes" are you talking about?

It does this without needing to add anything new since the core of the formulation is just to show that quantum systems are equivalent to certain kinds of stochastic ones.

I like the view that quantum theory is basically a stochastic theory, but would like to hear more details about those "certain kinds of stochastic ones".

Barandes wrote:

Seen from another point of view, this stochastic-quantum correspondence yields an alternative way to formulate quantum theory, in the language of trajectories unfolding stochastically in configuration spaces.

In my opinion already the concept of a trajectory is deeply flawed.

 

[DrChinese]

Mr. Chinese

It's Mr. DrChinese. Note that I am not a doctor of any kind that involves a degree. My musician friends simply call me Doc, so that's good as well. We're all friends here.

Oh, and I am not Chinese (according to 23 and me).

 

[Fra]

As I have said before, the non-markovianity condition looks just like the kind of violation of total probability which you get for incompatible observables

Yes I think it's related...

1) Different observers generally have different incompatible information, this may sometimes be cured by transformations that defines the communication, and this is then related to interaction terms. When no transformations exists, perhaps one can consider the symmetries to be emergent in some way.

2) Any one observer can choose an observational basis or also choose partial information in non-commutative observables; this generally leads to a balance or uncertainty relation between them for exampele conjugate variables.

if the quantum constructs required to produce the Bell correlations can be, effectively, translated into stochastic form? Obviously we haven't seen this yet - I guess its an open question, the state of this formulation further on down the road. But since this formulation is just about the bi-directional "dictionary" translation between quantum and stochastic systems then what I have said should be the case if Barandes' formulation is sound... right?

Yes I think these are some hard details missing in the puzzle.

Details aside, the vision I have that may be in line with some of the details in barandes ideas, that relate to stochastics is essential stochastic decision making - based on non-commutative and contextual information/observables. This has the potential to be extremely beautiful but to do from the concept to explicit mathematical models that are computable and not just a symbolic or formal expressions is I think extremely difficult. In essence my expectartion is that it would reduce ANY hamiltonian to "stochastics" of all interactions, and in this sense also add explanatory power to the nature of causation. Something that we do not have today! The is the main different from "rational action" in old game theory, because the problem is to DEFINE what is "rational". But what if its simply stochastic, and the rest is self organisation?

Markov processes in statitic state spaces here are clearly too simple.

/Fredrik

 

[iste]

Does it? This needs to be substantiated. What "definite outcomes" are you talking about?

Sorry, late and long reply.

Well if we look at a stochastic process, we may have basically a sequence of random variables across time defined on probability spaces. These random variables are not physical events but just provide predictive probabilities. We can then sample the variables, where they will only realize one outcome at a time. For instance, our random variable could give probabilities for a dice roll, and then we can sample the variable by rolling the dice which gives a single outcome at any time - a single physical event.

As another example, the variables could be referring to particle positions (like a dust particle floating in a glass of water) and if we take a single sample from a sequence of variables over time we get a single trajectory of where the dust particle moves over time in the glass of water, or something comparable to that. If we keep on sampling the sequence of variables indefinitely (i.e. repeating the experiment), we get many many trajectories whose frequencies should approach the variable probabilities as a consequence of the law of large numbers.

Now, at the center of Mr. Barandes' formulation is a dictionary which effectively translates from a generalized stochastic system' random variables into a unitary quantum system. It goes both ways so we can start from a quantum system and translate it to variables of a stochastic process. From this latter perspective, we note that there is nothing about the initial quantum system that necessarily leads to the notion of having these definite outcomes - on the contrary, most think this difficult to imagine, as you suggest further down in your comment. But then it is translated to the stochastic system which can be sampled for definite outcomes like you would for rolling a dice.

Why this is possible is that the sampled outcomes are something in addition to the objects of quantum mechanics so they do not contradict or change standard quantum mechanics in anyway. Without the assumption that quantum objects correspond to information about random variables, there is no reason for anyone to assume these sampled outcomes actually can exist like they commonsensically do for stochastic processes. But if quantum systems are equivalent to stochastic systems, then they are formally equivalent to systems which can produce those definite outcomes at every point in time. In this formulation, the quantum objects only correspond to (only translate to) information about the random variables in a stochastic process; they don't strictly correspond to any kind of physical object, event or outcome. They only carry information about statistics and so, according to Mr. Barandes' formulation, what has been interpreted in quantum mechanics as describing definite collapsed eigenstates or indefinite superpositions was never really about physical events or outcomes at all. Definite outcomes at every point in time can be sampled from coherent superpositions and decoherent mixtures; wave-function collapse corresponds purely to statistical conditioning without any physical consequence. Its worth noting that while I have said that there is no necessary reason to believe these stochastic outcomes exist from just looking at regular quantum formalism, they are arguably hinted at in the path integral formulation. Mr. Barandes' formulation is set up similarly to the path integral view where we are talking about how a particle's configuration evolves between two time points. The sampled trajectories between the two points in this formulation then correspond to the paths whose amplitudes are summed over in the path integral formulation. Naturally you can imagine that with its random behavior, repeating an experimental scenario indefinitely would sample all possible trajectories.

but would like to hear more details about those "certain kinds of stochastic ones".

The two papers in the beginning of the thread go into detail. But basically, we have this linear marginalization condition which allows us to calculate probabilities for particles being in configurations at one time point using an initial reference time point and transition probabilities between the two points.

What marks out the certain kind of stochastic process is that when we come to the issue of characterizing joint probabilities for specific trajectories of intermediate configurations between the two time points (dividing a trajectory into sub-trajectories e.g. like A-D into A-B-C-D with distinct transition probabilities), we just cannot do this - the system is indivisible. That is probably the biggest component that gives these stochastic systems quantum behavior. This is exactly the way in which you yourself said that the concept of the trajectory was flawed. These systems cannot give well-defined joint probabilities for the intermediate trajectory between two points even though, with some initial reference time point, we can define probabilities for any arbitrary time point. So we do have random variables with outcomes that can be sampled at every time point when starting from an initial time point, and form a trajectory of actual definite outcomes when you run the model or simulation or whatever. What is not well-defined is the (Markovian) joint probabilities when asked to specify intermediate parts to (the trajectory inbetween) the initial and final time points. So even though there are definite outcomes, it still has the same flawed trajectory issue as in quantum mechanics. The translation from stochastic to quantum is actually helpful here because you can effectively translate transition probabilities to what would more or less correspond to the transition amplitudes of the path integral formulation, and these are divisible (and therefore paths can be summed over to find them).

 

[iste]

It's Mr. DrChinese. Note that I am not a doctor of any kind that involves a degree. My musician friends simply call me Doc, so that's good as well. We're all friends here.

Oh, and I am not Chinese (according to 23 and me).

Oh I beg your pardon! I have been reading your name and then mentally referring to it as Mr. Chinese all this time, ha.

1) ... 2)

You might find this interesting:

https://royalsocietypublishing.org/doi/full/10.1098/rsta.2019.0036

Relating to your thoughts on observers, incompatible information, contextual.

You may also find this next paper interesting:

https://scholar.google.co.uk/scholar?cluster=10954599080507512058&hl=en&as_sdt=0,5&as_vis=1

(and maybe this https://www.sciencedirect.com/science/article/pii/S037015732300203X )

Its not quantum mechanics but from computational neuroscience but chimes with your ideas maybe. The paper essentially is generalizing a theory the "free energy" principle from biology to all things. The free energy principle is about biological life in terms of bayesian inference which can be framed as observers with beliefs and is a very big theory in neuroscience. The generalization to all things seems to basically originate from this paper as far as I see:

https://scholar.google.co.uk/scholar?cluster=17970774975628711245&hl=en&as_sdt=0,5&as_vis=1

So stochastic dynamics can be linked to the variational free energy of the theory. The author of the free energy paper is therefore in some ways linking stochastic dynamics together with ideas about inference and "beliefs" in a very general way. In some sections they go through formulations of different areas of physics (because they can be related to stochastic dynamics) including a section where they derive bits of quantum mechanics based on stochastic dynamics and complex roots which isn't the same at all but not exactly a trillion miles off conceptually from the Barandes papers. So I just thought you might find that interesting if you haven't already read about it, seems in the kind of direction of your ideas.

 

[WernerQH]

[...] the sampled outcomes are something in addition to the objects of quantum mechanics so they do not contradict or change standard quantum mechanics in anyway.

But if quantum systems are equivalent to stochastic systems, then they are formally equivalent to systems which can produce those definite outcomes at every point in time. In this formulation, the quantum objects only correspond to (only translate to) information about the random variables in a stochastic process; they don't strictly correspond to any kind of physical object, event or outcome.

This looks like the opposite of an interpretation. Barandes is hinting at a larger mathematical apparatus behind quantum theory, instead of mapping the elements of the theory to the real world. As for the stochastic variables purportedly having definite values at all times, it would help to see an application to a concrete physical example. Is "sampling" a mathematical or a physical concept? If it refers to "measurement", does the new formulation shed any light on which interactions count as measurements?

 

[Fra]

You might find this interesting:

https://royalsocietypublishing.org/doi/full/10.1098/rsta.2019.0036

Relating to your thoughts on observers, incompatible information, contextual.

You may also find this next paper interesting:

https://scholar.google.co.uk/scholar?cluster=10954599080507512058&hl=en&as_sdt=0,5&as_vis=1

(and maybe this https://www.sciencedirect.com/science/article/pii/S037015732300203X )

Its not quantum mechanics but from computational neuroscience but chimes with your ideas maybe. The paper essentially is generalizing a theory the "free energy" principle from biology to all things. The free energy principle is about biological life in terms of bayesian inference which can be framed as observers with beliefs and is a very big theory in neuroscience. The generalization to all things seems to basically originate from this paper as far as I see:

https://scholar.google.co.uk/scholar?cluster=17970774975628711245&hl=en&as_sdt=0,5&as_vis=1

So stochastic dynamics can be linked to the variational free energy of the theory. The author of the free energy paper is therefore in some ways linking stochastic dynamics together with ideas about inference and "beliefs" in a very general way. In some sections they go through formulations of different areas of physics (because they can be related to stochastic dynamics) including a section where they derive bits of quantum mechanics based on stochastic dynamics and complex roots which isn't the same at all but not exactly a trillion miles off conceptually from the Barandes papers. So I just thought you might find that interesting if you haven't already read about it, seems in the kind of direction of your ideas.

The conceptual idea in several your links are indeed just in line with what I mention! although there are many deep and difficult open problems with the approaches, so tricky that I think many are rejected by the ideas.

Some quotes from the references illustrating the conceptual hooks...

"these peculiar features of quantum theory are mathematically equivalent to a general notion of disagreement between information sources"

"tenet of the FEP is that everything must provide an accurate account of things that is as simple as possible—including itself"

"These mechanics have the same starting point as quantum, statistical and classical mechanics. The only difference is that careful attention is paid to the way that the internal states of something couple to its external states."

"“what must things do, in order to exist?” The FEP turns this question on its head and asks: “if things exist, what must they do?”

The challenge is to dress this in a computable model, map it's phenomenology to the standard model. The above quotes also explicitly relate to the fine tuning problems we are painfully aware of. The third point also emphasises that these idea are NOT "simple entropic reasoning"... because there is no fixed context, the context is simply the systems environment, this is the external/internal coupling! Basically relating internal and external complexions. This conceptually also associates to dualities.

/Fredrik

 

[iste]

This looks like the opposite of an interpretation. Barandes is hinting at a larger mathematical apparatus behind quantum theory, instead of mapping the elements of the theory to the real world. As for the stochastic variables purportedly having definite values at all times, it would help to see an application to a concrete physical example. Is "sampling" a mathematical or a physical concept? If it refers to "measurement", does the new formulation shed any light on which interactions count as measurements?

Well strictly it is a formulation of quantum mechanics, not an interpretation, based around showing that quantum mechanics is equivalent to, and so can be formulated as, generalized stochastic systems. In one, maybe more, of the papers, Barandes refers to the generalized stochastic system that quantum systems are equivalent to as a hidden-variable theory. But I think the interpretation or "physical picture" (in Barandes' words) follows because if the stochastic system generates definite outcomes, it is very hard not to interpret this just as particles always being in one definite place or configuration at a time and moving around under some random influence. Its only natural to interpret the outcomes of stochastic processes or random variables as physical events - e.g. the outcome of a dice roll is a physical event.

Obviously, this is all just a mathematical formalism, so the argument would be something like - if we can formulate quantum mechanics successfully in terms of particles being "classical-looking" then this seems like the most parsimonious way to interpret quantum mechanics because that is what we expected reality to look like before all the quantum confusion turned up.

Is "sampling" a mathematical or a physical concept?

Its a mathematical one in statistics. Like a statistician might sample from a model in the sense of looking at outcomes it generates. The outcomes we can see as representing physical events. Because the events occur randomly, the probabilities that predict the occurence of the events cannot be empirically observed unless you observe outcomes of random variables over and over again (i.e. repeat an experiment over and over again) and examine the frequencies.

I am not sure if the papers show concrete examples in the way you want though they do give quite detailed descriptions of all thr components that go into the model. I think the thing is that even though the definite outcomes are mentioned throughout the papers, they don't do any of the actual heavy lifting of describing behavior so they aren't really described all that much compared to probabilities, random variables, transition matrices and the quantum objects, etc. etc. He does refer to the double slit experiment in one of the papers (but not concretely) which I guess is a familiar example - the particle really does go through one slit at a time and cause the interference pattern through the gradual build up of individual outcomes on the screen under the stochastic picture.

If it refers to "measurement", does the new formulation shed any light on which interactions count as measurements?

Yes, measurement is in the theory and it is modelled by just explicitly including the measurement apparatus in the model as its own kind of stochastic system - it is just another physical interaction in the theory, thats it. The only special properties measurement has comes from basically how we design measurement devices. Decoherence naturally occurs from interactions with indivisible stochastic systems. Wave-function collapse just appears as statistical conditioning.