$1/L^2$ corrected soft photon theorem from a CFT$_3$ Ward identity

TL;DR

This paper demonstrates that $1/L^2$ corrections to the soft photon theorem in asymptotically flat spacetimes can be derived from a large N CFT$_3$ Ward identity, linking bulk corrections to boundary symmetries.

Contribution

It establishes a novel connection between $1/L^2$ corrected soft photon theorems and CFT$_3$ Ward identities, providing a boundary derivation of bulk corrections.

Findings

Derived a perturbed soft photon mode operator in AdS$_4$

Reproduced $1/L^2$ corrections from CFT$_3$ Ward identity

Linked classical soft theorems to boundary CFT symmetries

Abstract

Classical soft theorems applied to probe scattering processes on AdS$_4$ spacetimes predict the existence of $1/L^2$ corrections to the soft photon and soft graviton factors of asymptotically flat spacetimes. In this paper, we establish that the $1/L^2$ corrected soft photon theorem can be derived from a large $N$ CFT$_3$ Ward identity. We derive a perturbed soft photon mode operator on a flat spacetime patch in global AdS$_4$ in terms of an integrated expression of the boundary CFT current. Using the same in the CFT$_3$ Ward identity, we recover the $1/L^2$ corrected soft photon theorem derived from classical soft theorems.