Comment on "Bell inequalities and quantum mechanics" by J. H. Eberly

TL;DR

This paper critically examines Eberly's derivation of Bell inequalities, highlighting errors and clarifying the correct assumptions needed for their derivation, emphasizing the importance of rigorous logic in quantum foundations.

Contribution

It identifies specific errors in Eberly's derivation and clarifies the correct assumptions necessary for Bell inequalities, emphasizing the need for careful logical analysis.

Findings

Eberly's derivation contains an incorrect equation.

Eberly's approach does not use two-particle states or locality.

Violations of Bell's inequalities do not necessarily require entanglement in Eberly's framework.

Abstract

Errors in Eberly's derivation of several Bell inequalities are pointed out: (1) it is based on an equation that is incorrect; (2) it uses neither two-particle states nor locality to derive Bell's inequalities and; (3) it does not use entanglement to obtain violations of Bell's inequalities. Even leading and outstanding physicists -- as certainly is the case of Prof. Eberly -- sometimes make elementary mistakes, and this by no means diminishes the importance of their scientific contribution. In general, this is a consequence of an excessive attachment to an idea (nowadays it has become fashionable to be against realism). This shows the importance of trying to keep an open mind.