The gravitational Compton amplitude at third post-Minkowskian order

TL;DR

This paper calculates the gravitational Compton amplitude at third post-Minkowskian order using an effective field theory approach, revealing divergence structures and connecting to black hole perturbation results.

Contribution

It introduces a novel method to compute gravitational Compton amplitudes at high order, addressing divergence issues and linking to black hole perturbation theory.

Findings

Regulated infrared and forward divergences in the expansion.

Established a computational bridge to black hole perturbation theory.

Outlined applications for finite-size effects like spin and tidal features.

Abstract

We employ a single worldline effective field theory in a Schwarzschild--Tangherlini background to compute the gravitational Compton amplitude up to third post-Minkowskian order. By exposing the structure of infrared and forward divergences of the post-Minkowskian expansion, we are able to regulate these divergences, thereby establishing an exact and useful computational bridge to results in black hole perturbation theory. We also outline possible applications for Compton amplitudes with finite-size effects, such as spin and tidal features.