A Critical Analysis of the Quantum Nonlocality Problem

Abstract

The alleged nonlocal character of quantum mechanics is inextricably related to the formulation of the Bell theorem. However, as we shall see, that relation is commonly incorrectly assessed. The departure from the clear line of reasoning that John Bell tried to convey has led to a polarization of part of the scientific community into radical irreconcilable positions. We show how the correct appreciation of Bell's work calls for reinterpreting the usual significance given to the Bell theorem yielding a more rational perspective of the problem. Given the relevance of the Bell-type inequalities in quantum information technology and quantum foundations, further clarification of their relation to the nonlocality conundrum deserves due attention. The exposition is also of didactic value. It shows the problems arising from incorrect inferences and superfluous metaphysical ideas.

On the Meaning of Local Realism

“…We cannot justify the reasons for our interpretation here, but Ref. [49] develops the argument why we sustain that Bell did not interpret his inequality as proof of quantum nonlocality.…”

On the Consistent Meaning of Local Realism

“…Remarkably, much of the physical community has missed that Bell did not base his quantum nonlocality arguments on his inequality. Bell and Einstein's arguments for quantum nonlocality are indeed very similar [37]. The purpose of the Bell theorem, and the Bell inequality, is to prove that we cannot supplement quantum mechanics with additional variables to render a local theory.…”

“…Although we avoid discussing the contentious issue of quantum nonlocality, we point out that an unbiased reading of Bell's papers [20,35,36] shows that he interpreted his inequalities as ruling out non-conspiratorial local hidden variables and not as ruling out orthodox quantum mechanics' locality. Of course, he believed that quantum mechanics is nonlocal but did not claim his inequality proves it [37].…”

“…According to them, the list of hypotheses should reduce to 2) and 3) because hidden variables are a consequence of locality. In our opinion, Bell wisely avoided that approach [37]. He preferred to argue for quantum nonlocality differently and only introduced his inequality to prove that a local completion is not possible unless we violate statistical independence.…”

“…Also, Harrigan and Spekkens[42] explain how Einstein (and we would add Bell[35]) argued for quantum nonlocality. A critical analysis on quantum nonlocality is presented in[37].…”