Gravitational radiation from the classical spinning double copy

TL;DR

This paper extends the classical double copy correspondence to include spinning sources, demonstrating that gravitational radiation amplitudes match gauge theory predictions, thus simplifying calculations of gravitational waves from astrophysical objects.

Contribution

It introduces a new extension of the classical double copy to spinning sources, including scalar and 2-form fields, with detailed computations confirming the correspondence.

Findings

Gravitational amplitudes match gauge theory predictions.

The double copy extends to spinning sources with additional fields.

Provides detailed calculations confirming the correspondence.

Abstract

We establish a correspondence between perturbative classical gluon and gravitational radiation emitted by spinning sources, to linear order in spin. This is an extension of the non-spinning classical perturbative double copy and uses the same color-to-kinematic replacements. The gravitational theory has a scalar (dilaton) and a 2-form field (the Kalb-Ramon axion) in addition to the graviton. In arXiv:1712.09250, we computed axion radiation in the gravitational theory to show that the correspondence fixes its action. Here, we present complete details of the gravitational computation. In particular, we also calculate the graviton and dilaton amplitudes in this theory and find that they precisely match with the predictions of the double copy. This constitutes a non-trivial check of the classical double copy correspondence, and brings us closer to the goal of simplifying the calculation of gravitational wave observables for astrophysically relevant sources.