Angular Momentum Loss Due to Tidal Effects in the Post-Minkowskian Expansion

TL;DR

This paper computes tidal effects on angular momentum loss during two-body gravitational interactions at leading Post-Minkowskian order using amplitude techniques, unifying gravitational-wave emission and static field contributions.

Contribution

It introduces an amplitude-based method to calculate tidal corrections to angular momentum loss, combining elastic and inelastic amplitudes with collider physics techniques, validated against Post-Newtonian results.

Findings

Calculated tidal corrections to angular momentum loss at leading Post-Minkowskian order.

Unified treatment of gravitational-wave emission and static gravitational field effects.

Validated results with independent Post-Newtonian limit calculations.

Abstract

We calculate the tidal corrections to the loss of angular momentum in a two-body collision at leading Post-Minkowskian order from an amplitude-based approach. The eikonal operator allows us to efficiently combine elastic and inelastic amplitudes, and captures both the contributions due to genuine gravitational-wave emissions and those due to the static gravitational field. We calculate the former by harnessing powerful collider-physics techniques such as reverse-unitarity, thereby reducing them to cut two-loop integrals, and validate the result with an independent calculation in the Post-Newtonian limit. For the latter, we can employ the results of arXiv:2203.11915 where static-field effects were calculated for generic gravitational scattering events using the leading soft graviton theorem.