Double-Copy Supertranslations

TL;DR

This work demonstrates that the convolutional double copy naturally transmits infrared asymptotic symmetries from gauge to gravitational multiplets, yielding $BMS$ supertranslations on the graviton side and corresponding two-form asymptotic symmetries, along with an infinite hierarchy of scalar charges. By performing a detailed null-infinity analysis with the method of regions and employing polyhomogeneous expansions in Lorenz gauge, the authors show that logarithmic falloffs are essential for nonvanishing charges and that the double-copy scalar participates in the symmetry structure. The results provide a concrete bridge between gauge IR structure, gravity, and p-form symmetries, with potential connections to soft theorems and celestial CFT, and point to generalizations to higher spins and other backgrounds. The framework clarifies how double-copy constructions encode a rich set of asymptotic charges and their angular dependence, offering a robust laboratory for IR aspects of field theories coupled via the DC dictionary.

Abstract

In the framework of the convolutional double copy, we investigate the asymptotic symmetries of the gravitational multiplet stemming from the residual symmetries of its single-copy constituents at null infinity. We show that the asymptotic symmetries of Maxwell fields in D=4 imply ``double-copy supertranslations", i.e. BMS supertranslations and two-form asymptotic symmetries, together with the existence of infinitely many conserved charges involving the double-copy scalar. With the vector fields in Lorenz gauge, the double-copy parameters display a radial expansion involving logarithmic subleading terms, essential for the corresponding charges to be nonvanishing.