Relativistic corrections to CHSH vs. Preferred frame

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Discussion Overview

The discussion revolves around the concept of a quantum preferred frame as proposed in a paper by J. Rembielinski and K. A. Smolinski. Participants explore the implications of this idea on the CHSH inequalities in the context of relativistic quantum mechanics, particularly focusing on the existence or non-existence of a preferred reference frame and its potential testability through experimental setups involving entangled particles.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants highlight the assertion that a preferred frame could resolve issues in relativistic quantum mechanics, particularly regarding non-local phenomena.
  • Others argue that the proposed experiment may not provide conclusive evidence for a preferred frame without assuming non-locality, suggesting that scenario a) might be expected under those assumptions.
  • One participant questions the applicability of Bell's theorem in photon entanglement experiments, proposing that fair sampling cannot be assumed, which complicates the interpretation of locality in this context.
  • Another participant introduces the idea of context-dependent variables as a form of locality, distinct from traditional local hidden variable theories.

Areas of Agreement / Disagreement

Participants express differing views on the assumptions underlying the proposed experiment and its implications for non-locality and preferred frames. There is no consensus on whether the experiment can definitively prove the existence of a preferred frame or the validity of the assumptions made by the authors of the paper.

Contextual Notes

Participants note the limitations of the proposed experiment, particularly regarding the velocities required to distinguish between the scenarios and the assumptions about non-locality and fair sampling in entanglement experiments.

DrChinese
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OK, here is an interesting assertion I haven't seen before. Thought I would see what some of the folks here think. The paper is:

Quantum Preferred Frame: Does It Really Exist? by J. Rembielinski, K. A. Smolinski (2009)

Abstract: "The idea of the preferred frame as a remedy for difficulties of the relativistic quantum mechanics in description of the non-local quantum phenomena was undertaken by such physicists as J. S. Bell and D. Bohm. The possibility of the existence of preferred frame was also seriously treated by P. A. M. Dirac. In this paper, we propose an Einstein-Podolsky-Rosen-type experiment for testing the possible existence of a quantum preferred frame. Our analysis suggests that to verify whether a preferred frame of reference in the quantum world exists it is enough to perform an EPR type experiment with pair of observers staying in the same inertial frame and with use of the massive EPR pair of spin one-half or spin one particles."

In essence, they argue that there is a specific - and TESTABLE - difference in the quantum predictions (spin correlation of entangled pairs of electrons or protons moving in opposite directions at a very high velocity) between these 2 important scenarios:

a) There IS a universal preferred reference frame (key to many non-local Bohmian type theories), and the standard CHSH inequalities hold (QM prediction of about 2.8 violates local realistic upper limit of 2.0 at all). If this were true, it would be powerful ammunition for Bohmian class theories and non-locality.

b) There IS NO preferred frame - as expected per virtually all formulations of relativity, BUT the standard CHSH predictions of QM require a relativistic correction which drops the predicted value below the local realistic upper limit of 2.0 when the associated velocity v exceeds about 80% of c. If this were true - you would expect it would be - it would lead to some very interesting ways to probe entanglement in the relativistic limit; and would rule out non-locality as described by most Bohmian theories.

The authors describe prior experiments in which entangled proton pairs have been observed at v of about .40 to .50 c, but these velocities are too low to see any measurable difference between a) and b) above. By increasing v, such experiments could distinguish between these scenarios and settle a very important point in quantum theory... assuming the authors' theoretical analysis is correct.
 
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It seems that they assume non-locality and then make speculations about different types of possible non-localities.
So performing proposed experiment can prove nothing if you do not assume non-locality. In that case scenario a) should be expected but not as a proof of universal preferred frame.
 
Interesting, thanks for posting.

zonde said:
It seems that they assume non-locality and then make speculations about different types of possible non-localities.

Are you thinking about the MWI locality ?
 
Pio2001 said:
Are you thinking about the MWI locality ?
No. I am thinking about locality you get when you conclude that fair sampling can not be assumed in photon entanglement experiments and consequently conclude that Bell's theorem is not applicable there. But not really like locality in usual LHV but more like context dependent variables.
 

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