Quantum nonlocality: How does nature do it?

TL;DR

This paper discusses the foundations of quantum nonlocality, proposing that rejecting hidden variables offers a more plausible explanation for quantum correlations than nonlocality or statistical independence violations.

Contribution

It introduces the third option of rejecting hidden variables as a basis for quantum outcomes, supported by recent principles that explain quantum nonlocality.

Findings

Rejecting hidden variables is a scientifically plausible explanation.

Recent principles help understand why nature produces quantum nonlocality.

This approach offers an alternative to nonlocality and statistical independence violations.

Abstract

In a recent note, Hance and Hossenfelder (arXiv:2211.01331) recall that "locally causal completions of quantum mechanics are possible, if they violate the assumption [called statistical independence or measurement independence] that the hidden variables do not in any way depend on measurement settings" and that, consequently, the experimental violations of Bell inequalities "show that maintaining local causality requires violating statistical independence". However, Hance and Hossenfelder also argue that "we should (...) look for independent experimental evidence that can distinguish the two different options: non-locality and statistical independence, or locality and violations of statistical independence" and that "the unwillingness to consider theories without statistical independence may be the reason we do not yet have a locally causal theory for the foundations of physics that is consistent with general relativity". Here, we recall that there is a third option, namely, rejecting that measurement outcomes are governed in any way by hidden variables. Moreover, we argue that some recent results in the search for principles singling out the sets of quantum correlations for Bell and Kochen-Specker contextuality scenarios point out that this third option is scientifically more plausible and answers the question of why and how nature produces quantum nonlocality.