Matter-gravity couplings and Lorentz violation

TL;DR

This paper develops a comprehensive framework to analyze matter-gravity interactions under Lorentz and CPT violation, deriving quantum and classical dynamics, and identifying experimental signals with high sensitivity.

Contribution

It introduces a systematic perturbative approach to study Lorentz-violating effects in gravity, deriving Hamiltonians and trajectories, and proposing observable tests across various experiments.

Findings

Derived nonrelativistic quantum Hamiltonian with Lorentz violation

Established classical trajectories in Lorentz-violating gravity

Identified experimental sensitivities to Lorentz-violating coefficients

Abstract

The gravitational couplings of matter are studied in the presence of Lorentz and CPT violation. At leading order in the coefficients for Lorentz violation, the relativistic quantum hamiltonian is derived from the gravitationally coupled minimal Standard-Model Extension. For spin-independent effects, the nonrelativistic quantum hamiltonian and the classical dynamics for test and source bodies are obtained. A systematic perturbative method is developed to treat small metric and coefficient fluctuations about a Lorentz-violating and Minkowski background. The post-newtonian metric and the trajectory of a test body freely falling under gravity in the presence of Lorentz violation are established. An illustrative example is presented for a bumblebee model. The general methodology is used to identify observable signals of Lorentz and CPT violation in a variety of gravitational experiments and observations, including gravimeter measurements, laboratory and satellite tests of the weak equivalence principle, antimatter studies, solar-system observations, and investigations of the gravitational properties of light. Numerous sensitivities to coefficients for Lorentz violation can be achieved in existing or near-future experiments at the level of parts in 10^3 down to parts in 10^{15}. Certain coefficients are uniquely detectable in gravitational searches and remain unmeasured to date.