CPT-Violating Gravitational Orbital Perturbations

TL;DR

This paper investigates how spontaneous CPT violation in a bumblebee gravity model affects orbital trajectories, revealing spin-dependent velocities and precession rates in a Schwarzschild background.

Contribution

It introduces a specific bumblebee model with spontaneous CPT violation and analyzes its back reaction on the metric, including spin-dependent orbital effects.

Findings

Discovery of spin-dependent orbital velocities.

Identification of spin-dependent precession rates.

Consistency of the model with standard Riemannian geometry.

Abstract

A model for spontaneous symmetry breaking using a specific form of the bumblebee model is analyzed in the context of a Schwarzschild background metric. The resulting back reaction of the symmetry-breaking field on the metric is computed to second order. Consistency with conventional (pseudo)Riemannian geometry is demonstrated. This background field is coupled to fermions via a spin-dependent CPT-violating coupling term of a type commonly considered in the Standard-Model Extension. The perturbations of various orbital trajectories are discussed. Specifically, a spin-dependent orbital velocity is found as well as a spin-dependent precession rate.