Université Paris Saclay, France, philippe.grangier@institutoptique.fr
With the Nobel Prize attributed to Aspect, Clauser, and Zeilinger, the international scientific community acknowledged the fundamental importance of the experimental violation of Bell’s inequalities [1]. It is however still debated what fails in Bell’s hypotheses, leading to these inequalities, and usually summarized as “local realism", or maybe more appropriately “classical local realism". The most common explanation is “quantum non-locality", that remains however fully compatible with relativistic causality; this makes wondering whether any non-local phenomenon is really involved in these experiments. In this talk we recapitulate another option, called “predictive incompleteness", closely related to the idea that the usual state vector ψ is incomplete indeed [2,3], as it was claimed by Einstein, Podolsky and Rosen. We also argue that ψ should be completed, not by looking for any “hidden variables", but rather by specifying the measurement context, as it was claimed by Bohr [4]; this is required to define actual probabilities over a set of mutually exclusive physical events. Finally we propose a possible unified mathematical framework including both quantum and classical physics, appearing as required incommensurable facets in the description of nature [5, 6].
[1] For an overview of Bell-test experiments until 2015, see: Alain Aspect, “Closing the Door on Einstein and Bohr’s Quantum Debate”, Physics 8, 123 (2015) https://physics.aps.org/articles/v8/123
[2] P. Grangier, “Contextual inferences, nonlocality, and the incompleteness of quantum mechanics”, Entropy 23, 1660 (2021); https://www.mdpi.com/1099-4300/23/12/1660
[3] P. Grangier, “Why ψ is incomplete indeed: a simple illustration”, https://arxiv.org/abs/2210.05969
[4] N. Farouki and P. Grangier, “The Einstein-Bohr debate: finding a common ground of understanding ?”, Found. Sci. (2021); https://doi.org/10.1007/s10699-020-09716-7
[5] P. Grangier, “Completing the Quantum Formalism in a Contextually Objective Framework”, Found. Phys. 51,76 (2021) [arXiv:2003.03121]
[6] M. Van Den Bossche and P. Grangier, “Contextual unification of classical and quantum physics”, https://arxiv.org/abs/2209.01463