Speaker
Description
Gravitational memory describes the lasting change in the separation and relative velocity of freely-falling detectors after the passage of gravitational waves. The phenomenon is intimately related to Weinberg's soft graviton theorems and BMS symmetries at future null infinity. In this talk, I will elucidate the relation between BMS transformations and the description of gravitational memory in synchronous coordinates, commonly used in gravitational wave detectors like LISA. I will show that gravitational memory corresponds to large residual diffeomorphisms in this gauge, such as volume-preserving spatial rescalings. I will then derive the associated soft theorems for equal-time correlation functions. These turn out to be the flat space analogues of the well-known inflationary consistency relations.
