Bell-type Polarization Exp: Uncorrelated Photon Pairs & End of Nonlocality?

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Discussion Overview

The discussion centers on a Bell-type polarization experiment involving uncorrelated optical photon pairs, as presented by M. Iannuzzi et al. The participants explore the implications of the experiment's findings on the concept of nonlocality in quantum mechanics, questioning the validity of the results and their alignment with established quantum predictions.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants note that the experiment claims to demonstrate a violation of Bell-type inequalities without the presence of entanglement, which raises skepticism regarding its alignment with quantum mechanics.
  • One participant suggests that the experiment may be proposing a variation of Bertlmann's socks, referencing a mathematical disproof by John Bell in 1981.
  • Concerns are raised about the methodology of the experiment, particularly regarding the use of independent lasers instead of entangled photon pairs, and the implications of photon number distributions on the analysis of the results.
  • Another participant points out that the observed photon bunching is unexpected for two independent lasers unless they are strongly filtered, which could lead to quasithermal light sources.
  • There is a mention of the need to consider the variability in photon numbers arriving at the detectors, which could affect the validity of the analysis related to the CH inequality.

Areas of Agreement / Disagreement

Participants express skepticism and disagreement regarding the experiment's conclusions, with multiple competing views on its validity and implications for the nonlocality paradigm. The discussion remains unresolved.

Contextual Notes

Limitations include assumptions about photon states and distributions, as well as the implications of using independent lasers versus entangled pairs in the context of Bell-type experiments.

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A very interesting Bell-type experiment using uncorrelated photons
A very interesting experiment:
Bell-type Polarization Experiment With Pairs Of Uncorrelated Optical Photons
M. Iannuzzi, et al.
in arXiv:2002.02723 [quant-ph] or Physics Letters A 384 (2020) 126200
The autor(s) conclude:
"We may therefore understand that the measurement precedure adopted in the Bell-type experiments yields the polarization relation between the two members of a pair, either entangled or not entangled, in their finalpreparation state.
In particular, for either quantum or classical physical systems, sinusoidal correlations relation of p12(a, b) substituited into the CH inequality, may cause its violation. Consequently we believe that the CH inequality will be conclusively tested only by relating it to Bell-type experiments with an analysing instrument and a final state-preparation instrument that do not coincide."
This seems to be very strange. This is the end of the "nonlocality" paradigm?
 
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As far as I can see, this experiment claims violation of Bell-type inequalities without entanglement. This is in contradiction with the predictions of quantum mechanics. I am very skeptical.
 
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If i understand their work correctly, they are claming a variation of Bertlmann's socks. Wasn't this disproved mathematically by John Bell in 1981?
 
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The number of issues with this manuscript is very long. Just to start with, the photon bunching they see is not expected for two independent lasers, unless they are filtered strongly. In that case they become quasithermal light sources.
Along the same lines, they use two lasers instead of entangled photon pairs, but do not consider the Poissonian (or Bose-Einstein-like for quasithermal light) photon number distribution lasers show. So there are no photon pairs arriving, but strongly varying numbers of photons. This of course needs to be taken into account in a correct analysis and if I remember correctly, the derivation of the CH-inequality assumes exact photon pair states and not sometimes 2 photons, sometimes just 1 and sometimes 7.
 
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