Gravitational Wave Memory in Beyond GR Theories

TL;DR

This paper computes gravitational-wave memory in scalar Gauss–Bonnet gravity, revealing deviations from GR that enhance waveform differences and could aid future gravity tests.

Contribution

First calculation of memory effects in a beyond-GR theory using full inspiral-merger-ringdown waveforms, highlighting their observational significance.

Findings

Percent-level deviations from GR in memory signals.

Memory inclusion increases waveform mismatch, aiding gravity tests.

Scalar contributions to tensor memory are strongly suppressed.

Abstract

Gravitational-wave memory is a low-frequency, non-oscillatory signal that provides a promising probe of strong-field gravity. We present the first computation of memory from full inspiral--merger--ringdown waveforms in a theory beyond GR, focusing on scalar Gauss--Bonnet gravity. We find percent-level deviations from GR, mainly driven by modified merger dynamics, while scalar-induced contributions to tensor memory are strongly suppressed. We found that including memory greatly enhances the mismatch between GR and beyond-GR waveforms, highlighting its potential as a complementary observable for tests of gravity with next-generation detectors.