Classical Gravity from Loop Amplitudes

TL;DR

This paper introduces an efficient method for extracting classical gravitational observables from scattering amplitudes, simplifying calculations and confirming recent high-order results in Einstein gravity and supergravity.

Contribution

It presents a new technique to streamline the extraction of classical gravity information from loop amplitudes, applicable to high-order Post-Minkowskian calculations.

Findings

Successfully computed second Post-Minkowskian order integrals for black-hole scattering.

Confirmed universality and high-energy behavior at third Post-Minkowskian order.

Simplified the soft-region integration method for classical gravity applications.

Abstract

We describe an efficient method for extracting the parts of $D$-dimensional loop integrals that are needed to derive observables in classical general relativity from scattering amplitudes. Our approach simplifies the soft-region method of integration by judiciously combining terms before the final integrations. We demonstrate the method by computing the required integrals for black-hole scattering to the second Post-Minkowskian order in Einstein gravity coupled to scalars. We also confirm recent results at the third Post-Minkowskian order regarding universality and high-energy behavior of gravitational interactions in maximal supergravity.