Gravitational Wave Memory as a Probe of Parity Violation and Cosmology

Given the fundamental interplay between matter and curvature in shaping general relativity (GR), it is natural to ask: what are the consequences when matter explicitly violates symmetries—such as parity—that are otherwise respected in GR? In this context, parity-violating theories of gravity, such as dynamical Chern–Simons (dCS) gravity, have gained attention as testbeds for exploring both parity violation and potential deviations from GR.

A particularly intriguing observable in this regard is the gravitational wave (GW) memory effect, a persistent feature predicted by all metric theories of gravity. In our earlier work (arXiv:2402.18083), we investigated this effect within the framework of an expanding universe in GR. In this talk, I will show how this formalism can be extended to dCS gravity and demonstrate how next-generation detectors can leverage the GW memory effect to probe deviations from GR, and help in selecting cosmological models.