Universality Principle for Orbital Angular Momentum and Spin in Gravity with Torsion

TL;DR

This paper proposes a universality principle in gravity theories with torsion, asserting that orbital angular momentum and spin are indistinguishable, leading to the conclusion that spinless particles follow autoparallel trajectories rather than geodesics.

Contribution

It introduces a universality principle linking orbital angular momentum and spin in torsion-based gravity theories, impacting particle trajectory predictions.

Findings

Spinless particles move along autoparallel trajectories.

Gravity theories with torsion must treat orbital angular momentum and spin equivalently.

Compatibility with particle physics constrains torsion theories.

Abstract

We argue that compatibility with elementary particle physics requires gravitational theories with torsion to be unable to distinguish between orbital angular momentum and spin. An important consequence of this principle is that spinless particles must move along autoparallel trajectories, not along geodesics.