Signals for Lorentz Violation in Post-Newtonian Gravity

TL;DR

This paper develops a framework to detect Lorentz violation in gravity through post-Newtonian metrics, analyzing experimental sensitivities and providing methods to test fundamental physics with various gravitational experiments.

Contribution

It introduces a method to derive post-Newtonian metrics incorporating Lorentz violation coefficients and applies it to multiple experimental setups, expanding the tools for testing fundamental symmetries in gravity.

Findings

Sensitivity estimates range from 10^{-4} to 10^{-15}.

Multiple experimental approaches can detect Lorentz violation effects.

The methodology applies to various gravitational systems and experiments.

Abstract

The pure-gravity sector of the minimal Standard-Model Extension is studied in the limit of Riemann spacetime. A method is developed to extract the modified Einstein field equations in the limit of small metric fluctuations about the Minkowski vacuum, while allowing for the dynamics of the 20 independent coefficients for Lorentz violation. The linearized effective equations are solved to obtain the post-newtonian metric. The corresponding post-newtonian behavior of a perfect fluid is studied and applied to the gravitating many-body system. Illustrative examples of the methodology are provided using bumblebee models. The implications of the general theoretical results are studied for a variety of existing and proposed gravitational experiments, including lunar and satellite laser ranging, laboratory experiments with gravimeters and torsion pendula, measurements of the spin precession of orbiting gyroscopes, timing studies of signals from binary pulsars, and the classic tests involving the perihelion precession and the time delay of light. For each type of experiment considered, estimates of the attainable sensitivities are provided. Numerous effects of local Lorentz violation can be studied in existing or near-future experiments at sensitivities ranging from parts in 10^4 down to parts in 10^{15}.