Analyzing "magnetic moments in curved spacetime": pitfalls in GR

TL;DR

This paper critically examines previous claims about magnetic moments in curved spacetime, identifying errors in the application of general relativity and clarifying the correct interpretation of physical versus coordinate distances.

Contribution

It provides a detailed analysis of classical approximations in prior work, highlighting common pitfalls and clarifying the correct approach to predictions in curved spacetime.

Findings

Differences vanish when distinguishing coordinate and physical distances.

Identifies specific errors in previous GR-based magnetic moment calculations.

Clarifies the correct interpretation of measurements in curved spacetime.

Abstract

We analyze the classical approximations made in "The general relativistic effects to the magnetic moment in the Earth's gravity", originally published as "Post-Newtonian effects of Dirac particle in curved spacetime - I : magnetic moment in curved spacetime", and work out precisely where in the argument the mistakes are made. We show explicitly that any difference vanishes when properly distinguishing between coordinate and physical distance. In doing this, we illustrate some of the pitfalls in using GR to make predictions.