Perturbative Quantization of Gravity Theories

TL;DR

This paper explores how string theory relations and unitarity methods enable the perturbative quantization of gravity, providing a practical approach to compute gravity scattering amplitudes and suggesting improved ultraviolet behavior in N=8 supergravity.

Contribution

It introduces a method to quantize gravity perturbatively using string theory relations and unitarity, connecting gravity amplitudes to gauge theory results.

Findings

Gravity $S$-matrix elements can be computed from gauge theory amplitudes.

String theory relations facilitate perturbative quantum gravity calculations.

N=8 supergravity may be less divergent in the ultraviolet than previously believed.

Abstract

We discuss string theory relations between gravity and gauge theory tree amplitudes. Together with $D$-dimensional unitarity, these relations can be used to perturbatively quantize gravity theories, i.e. they contain the necessary information for calculating complete gravity $S$-matrices to any loop orders. This leads to a practical method for computing non-trivial gravity $S$-matrix elements by relating them to much simpler gauge theory ones. We also describe arguments that N=8 D=4 supergravity is less divergent in the ultraviolet than previously thought.