Bell violations + perfect correlations via conservative Brownian motion

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Discussion Overview

The discussion revolves around the implications of recent papers on Bell violations and perfect correlations through the lens of conservative Brownian motion and stochastic mechanics. Participants explore theoretical models, criticisms, and experimental evidence related to quantum mechanics, particularly focusing on non-locality, multi-time correlations, and the interpretation of quantum states.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning
  • Experimental/applied

Main Points Raised

  • Some participants highlight a recent paper that presents a model of Bell scenarios from a stochastic mechanics perspective, noting its alignment with orthodox quantum mechanics predictions.
  • Concerns are raised about Markovian stochastic mechanics being excessively non-local and having incorrect multi-time correlations, with suggestions that non-Markovian diffusion could resolve these issues.
  • One participant points out that the 2024 Beyer-Paul paper and the 2023 Kuipers paper overlook critical experimental results that contradict their stochastic arguments, particularly regarding the nature of entangled states and non-locality.
  • Critiques include the assertion that the initial preparation of states does not necessitate entanglement, challenging the assumptions made in the discussed papers.
  • Participants reference experiments, such as delayed-choice entanglement swapping, to illustrate the complexities of entanglement and the implications of non-locality in quantum mechanics.
  • There is a discussion about the Wallstrom criticism of stochastic mechanics, with some suggesting that recent insights may invalidate this criticism by showing that a divergent part of the stochastic Lagrangian can lead to the desired quantization condition without arbitrary assumptions.
  • Some participants note parallels between Markovian approaches and Bohmian mechanics, suggesting that realism may be linked to the issues with multi-time correlations.

Areas of Agreement / Disagreement

Participants express differing views on the validity of the stochastic mechanics models discussed, with some supporting the recent papers while others argue that they fail to account for critical experimental evidence. The discussion remains unresolved, with multiple competing perspectives on the implications of these models.

Contextual Notes

Limitations include the dependence on specific interpretations of quantum mechanics, the unresolved nature of multi-time correlations, and the assumptions regarding the preparation of quantum states in the discussed models.

  • #31
Fra said:
A Perimeter talk https://pirsa.org/11100113
"Does Time Emerge from Timeless Laws, or do Laws of Nature Emerge in Time?"


Thanks for the link! I'll definitely have to take a look and digest.
 
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  • #32
I just wanted to update my thoughts on the question by Fredrik about how the "Barandes transition matrices (or lack of) emerge".

It seems to me that if the Barandes non-Markovianity condition is related to correct multi-time correlations due to its interferences, then the amelioration of incorrect Nelsonian/Bohmian multi-time correlations by measurement imply that the non-commutativity of position and momentum are in some way the source of the non-Markovianity, since clearly measurement related disturbance would be what is ameliorating the faulty correlations when explicitly accounting for measurement.

I then saw that the effect of the non-commuting Non-Selective Measurements on temporal behavior are described in the following paper:

https://arxiv.org/abs/quant-ph/0306029

"So the NSM of the position ˆx at time t = 0 not only has changed immediately the probability distribution of the momenta p, as we have analyzed in b1), but it has changed also the probability distribution of x at any time t > 0. Now the reader may wonder why the probability distributions ρP (x|t) and ρM (x|t) were the same at t = 0, see (3.16)-(3.17), but they are different at any time t > 0. The explanation is that during the evolution, which is given by ˙x = p and couples x with p, the distributions in x are influenced by the initial distributions in p which, as shown in (3.18) and (3.19), are different in the two cases in which we perform, case b), or not perform, case a), the NSM of ˆx at t = 0. So the NSM of ˆx influences immediately the distribution of probability of the conjugate variable p. Next, since the momenta p are coupled to x via their equations of motion, the changes in the distribution of p are inherited by the distribution of the positions at any instant of time t > 0."

So the authors observe how the non-commutativity means the measurement is disturbing the behavior at other instances of time. It seems that this kind of disturbance would be what is ameliorating the faulty Nelsonian/Bohmian multi-time correlations. Maybe then the Barandes non-Markovianity and its interferences are linked to the non-commutativity which also exists in the Barandes theory like in QM - measurements at one time disturb the trajectory / transition statistics for other times, violating (total) joint probability consistency conditions for its trajectory's transition matrices.
 

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