Spin dynamics in gravitational fields of rotating bodies and the equivalence principle

TL;DR

This paper explores how spin behaves in gravitational fields of rotating bodies, showing classical and quantum spin precession are consistent and depend on tetrad choice, advancing understanding of spin-gravity interactions.

Contribution

It provides a relativistic equation for classical spin in curved spacetime and demonstrates the agreement between classical and quantum spin precession in rotating gravitational fields.

Findings

Classical and quantum spin precession are in perfect agreement.

Spin precession depends critically on tetrad choice.

Results align with earlier tetrad gauge computations.

Abstract

We discuss the quantum and classical dynamics of a particle with spin in the gravitational field of a rotating source. A relativistic equation describing the motion of classical spin in curved spacetimes is obtained. We demonstrate that the precession of the classical spin is in a perfect agreement with the motion of the quantum spin derived from the Foldy-Wouthuysen approach for the Dirac particle in a curved spacetime. We show that the precession effect depends crucially on the choice of a tetrad. The results obtained are compared to the earlier computations for different tetrad gauges.