Double-soft limit and celestial shadow OPE from charge bracket

TL;DR

This paper explores the connection between soft theorems and celestial conformal field theory, providing methods to resolve ambiguities in celestial OPEs and extending the framework to arbitrary spins in gravity and Yang-Mills theories.

Contribution

It introduces a prescription for solving double-soft limit ambiguities and an algorithm for computing shadow celestial OPEs, generalizing to arbitrary spins.

Findings

Resolved double-soft limit ambiguities in celestial OPEs.

Developed an algorithm for shadow celestial OPEs applicable to various spins.

Extended the celestial OPE framework to gravity and Yang-Mills theories.

Abstract

The dual formulations of an infinite tower of tree-level soft theorems in asymptotically flat spacetimes for scattering amplitudes in the standard energy-momentum basis and for correlators of a 2D celestial conformal field theory imply a correspondence between the celestial operator product expansion (OPE) and the higher spin charge bracket. We apply such correspondence to provide first a prescription to solve the double-soft limit ambiguity in the mixed-helicity sector of celestial OPEs. Furthermore, demanding the charge OPE/bracket correspondence to remain valid when operators are shadow transformed, we construct an algorithm to compute shadow celestial OPEs. We first test the algorithm by recovering results in the previous literature involving the celestial energy-momentum tensor; we then apply it to both gravity and Yang-Mills theory and generalize the OPE derivation to arbitrary spins.