Comment on "Quantum mechanics for non-inertial observers"

TL;DR

This paper critiques a recent claim about gravitational potential and internal-external coupling in quantum mechanics, clarifying a mistake that led to an incorrect conclusion about gravitational redshift effects.

Contribution

It identifies and corrects a specific error in a recent publication claiming a necessary cancellation of relativistic coupling in gravitational fields.

Findings

The claimed cancellation of relativistic coupling is incorrect.

The paper clarifies the role of gravitational redshift in quantum systems.

A specific mistake in the prior paper is pinpointed and corrected.

Abstract

In a recent paper (arXiv:1701.04298 [quant-ph]) Toro\v{s}, Gro{\ss}ardt and Bassi claim that the potential necessary to support a composite particle in a gravitational field must necessarily cancel the relativistic coupling between internal and external degrees of freedom. As such a coupling is responsible for the gravitational redshift measured in numerous experiments, the above statement is clearly incorrect. We identify the simple mistake in the paper responsible for the incorrect claim.