Modified celestial amplitude in Einstein gravity

TL;DR

This paper evaluates a modified celestial amplitude for gravitons and gluons in Einstein gravity, showing it is finite, behaves like a correlation function on null-infinity, and admits conformal soft factorization.

Contribution

It introduces a finite, modified celestial amplitude framework in Einstein gravity that behaves as a 3D correlation function and supports conformal soft factorization.

Findings

Modified amplitude is finite for gravitons in Einstein gravity.

Amplitude acts as a correlation function at null-infinity.

Supports conformal soft factorization.

Abstract

In this paper we evaluate the modified celestial amplitude for gravitons and gluons, as defined in arXiv:1801.10171[hep-th]. We find that the modified (tree) amplitude is finite for gravitons in Einstein gravity. The modified amplitude behaves like correlation function of operators inserted at various points of null-infinity in the Minkowski space-time. Therefore, unlike the standard celestial amplitudes, these are three dimensional objects. We also show that this amplitude admits conformal soft factorization recently studied in the literature.