Comments on the double copy construction for gravitational theories

TL;DR

This paper critically examines the double copy approach for linearized gravity, identifying key technical challenges and proposing potential solutions to improve the correspondence between gauge theories and gravity.

Contribution

It highlights specific issues in the double copy construction for linearized gravity and discusses possible resolutions to enhance its consistency and applicability.

Findings

Identifies degree of freedom matching problems in the double copy

Discusses constraints between graviton and dilaton sources

Proposes potential methods to resolve technical issues

Abstract

We revisit the double copy description for linearized gravity and point out various technical issues and subtleties, associated with setting up the double copy description, including the problem of matching degrees of freedom on both sides of the double copy dictionary and the related issue of the constraint between graviton and dilaton sources. We introduce and discuss possible resolutions of these issues.