Speaker
Description
Gravitational-wave (GW) memory is a non-oscillatory component of GW signals that leaves a permanent displacement in spacetime after the wave has passed. It is a generic prediction of General Relativity, arising at second order from the nonlinear dynamics of gravity, yet it has not been detected so far. In this talk, I will present recent results on the detectability of GW memory with future detectors such as LISA and discuss its impact on parameter estimation. I will then show how GW memory can serve as a probe of new physics. First, I will present memory predictions from numerical-relativity waveforms in modified gravity theories, including Einstein-scalar-Gauss-Bonnet gravity and its Ricci-coupled extension, where additional polarization modes modify the memory signal. Finally, I will discuss how the low-frequency nature of GW memory can be exploited in multiband searches to access mergers beyond the nominal frequency range of a detector, with applications to populations of light Primordial Black Holes. This highlights GW memory not only as a fundamental prediction of gravity, but also as a powerful tool for testing new physics.