In general relativity, gravitational memory describes the lasting change in the separation and relative velocity of freely falling detectors after the passage of gravitational waves (GWs). In this paper, we elucidate the relation between Bondi-Metzner-Sachs transformations at future null infinity and the description of gravitational memory in local synchronous coordinates, commonly used in GW detectors like LISA. We show that gravitational memory corresponds to large residual diffeomorphisms in this gauge, such as volume-preserving spatial rescalings. We reproduce the associated soft theorems for scattering amplitudes. Finally, we derive novel soft theorems for equal-time (in-in) correlation functions, which are recognized as the flat space analogues of inflationary consistency relations with a soft tensor mode. Furthermore, these relations provide a pathway toward uncovering deeper connections between gravitational memory and cosmological correlators.
De Luca, Valerio, et al. "Gravitational memory and soft theorems: The local perspective." Physical Review. D., vol. 112, no. 2, Jul. 2025. https://doi.org/10.1103/gbg1-mz49
De Luca, Valerio, Khoury, Justin, & Wong, Sam S. C. (2025). Gravitational memory and soft theorems: The local perspective. Physical Review. D., 112(2). https://doi.org/10.1103/gbg1-mz49
De Luca, Valerio, Khoury, Justin, and Wong, Sam S. C., "Gravitational memory and soft theorems: The local perspective," Physical Review. D. 112, no. 2 (2025), https://doi.org/10.1103/gbg1-mz49
@article{osti_3011547,
author = {De Luca, Valerio and Khoury, Justin and Wong, Sam S. C.},
title = {Gravitational memory and soft theorems: The local perspective},
annote = {In general relativity, gravitational memory describes the lasting change in the separation and relative velocity of freely falling detectors after the passage of gravitational waves (GWs). In this paper, we elucidate the relation between Bondi-Metzner-Sachs transformations at future null infinity and the description of gravitational memory in local synchronous coordinates, commonly used in GW detectors like LISA. We show that gravitational memory corresponds to large residual diffeomorphisms in this gauge, such as volume-preserving spatial rescalings. We reproduce the associated soft theorems for scattering amplitudes. Finally, we derive novel soft theorems for equal-time (in-in) correlation functions, which are recognized as the flat space analogues of inflationary consistency relations with a soft tensor mode. Furthermore, these relations provide a pathway toward uncovering deeper connections between gravitational memory and cosmological correlators.},
doi = {10.1103/gbg1-mz49},
url = {https://www.osti.gov/biblio/3011547},
journal = {Physical Review. D.},
issn = {ISSN 2470-0029},
number = {2},
volume = {112},
place = {United States},
publisher = {American Physical Society (APS)},
year = {2025},
month = {07}}
Bondi, Hermann; Van der Burg, M. G. J.; Metzner, A. W. K.
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, Vol. 269, Issue 1336, p. 21-52https://doi.org/10.1098/rspa.1962.0161
Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, Vol. 270, Issue 1340, p. 103-126https://doi.org/10.1098/rspa.1962.0206