A Chiral Perturbation Expansion for Gravity

TL;DR

This paper proposes a novel perturbation theory for Einstein gravity inspired by gauge theory formulations, with potential connections to twistor-string theory and a new perspective on gravitational amplitudes.

Contribution

It introduces a chiral perturbation expansion for gravity, treating helicities asymmetrically, and suggests a twistor-string interpretation for gravitational amplitudes.

Findings

Power counting rules for gravitational amplitudes

Potential twistor-string formulation for gravity

Asymmetric treatment of helicities in perturbation theory

Abstract

A formulation of Einstein gravity, analogous to that for gauge theory arising from the Chalmers-Siegel action, leads to a perturbation theory about an asymmetric weak coupling limit that treats positive and negative helicities differently. We find power counting rules for amplitudes that suggest the theory could find a natural interpretation in terms of a twistor-string theory for gravity with amplitudes supported on holomorphic curves in twistor space.