EPR before EPR: a 1930 Einstein-Bohr thought experiment revisited

TL;DR

This paper revisits a 1930 thought experiment by Einstein and Bohr, revealing it as an early example of nonlocal quantum correlations predating the EPR paper, challenging previous interpretations of quantum uncertainty and relativity.

Contribution

It provides a modern reinterpretation of a historical thought experiment, highlighting its significance as an early demonstration of quantum nonlocality.

Findings

Neither Einstein nor Bohr was correct in their original arguments.

The thought experiment exemplifies nonlocal EPR correlations before 1935.

It offers new insights into the historical development of quantum mechanics.

Abstract

In 1930 Einstein argued against consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of mass of the box which emitted a photon. Bohr seemingly triumphed over Einstein by arguing that the Einstein's own general theory of relativity saves the consistency of quantum mechanics. We revisit this thought experiment from a modern point of view at a level suitable for undergraduate readership and find that neither Einstein nor Bohr was right. Instead, this thought experiment should be thought of as an early example of a system demonstrating nonlocal "EPR" quantum correlations, five years before the famous Einstein-Podolsky-Rosen paper.