Gravitational Wave Tests of General Relativity with Ground-Based Detectors and Pulsar Timing Arrays

TL;DR

This review discusses how gravitational wave observations from ground-based detectors and pulsar timing arrays enable tests of Einstein's General Relativity in the strong-field, dynamical regime, expanding beyond previous weak-field constraints.

Contribution

It provides a comprehensive overview of theoretical predictions, detector capabilities, and data analysis methods for testing gravity theories with gravitational waves in the strong-field regime.

Findings

Gravitational waves probe the non-linear, dynamical strong-field regime of gravity.

Current detectors can test modifications to General Relativity in compact binary coalescences.

The review highlights the potential of gravitational wave observations to constrain alternative gravity theories.

Abstract

This review is focused on tests of Einstein's theory of General Relativity with gravitational waves that are detectable by ground-based interferometers and pulsar timing experiments. Einstein's theory has been greatly constrained in the quasi-linear, quasi-stationary regime, where gravity is weak and velocities are small. Gravitational waves will allow us to probe a complimentary, yet previously unexplored regime: the non-linear and dynamical strong-field regime. Such a regime is, for example, applicable to compact binaries coalescing, where characteristic velocities can reach fifty percent the speed of light and compactnesses can reach a half. This review begins with the theoretical basis and the predicted gravitational wave observables of modified gravity theories. The review continues with a brief description of the detectors, including both gravitational wave interferometers and pulsar timing arrays, leading to a discussion of the data analysis formalism that is applicable for such tests. The review ends with a discussion of gravitational wave tests for compact binary systems.