New Gravitational Memories

TL;DR

This paper introduces a new type of gravitational 'spin memory' effect caused by radiative angular momentum flux, linking it to recent soft graviton theorems and expanding understanding of gravitational memory phenomena.

Contribution

It identifies and formulates a novel gravitational spin memory effect connected to subleading soft graviton theorems, extending the theoretical framework of gravitational memory effects.

Findings

Discovered a new gravitational spin memory effect.

Linked spin memory to subleading soft graviton theorem.

Extended the theoretical understanding of gravitational memory.

Abstract

The conventional gravitational memory effect is a relative displacement in the position of two detectors induced by radiative energy flux. We find a new type of gravitational `spin memory' in which beams on clockwise and counterclockwise orbits acquire a relative delay induced by radiative angular momentum flux. It has recently been shown that the displacement memory formula is a Fourier transform in time of Weinberg's soft graviton theorem. Here we see that the spin memory formula is a Fourier transform in time of the recently-discovered subleading soft graviton theorem.