Infrared behavior of graviton-graviton scattering

TL;DR

This paper analyzes the infrared behavior of graviton-graviton scattering at one loop, showing that divergences are infrared in origin and the cross section is finite when bremsstrahlung is included, confirming the consistency of quantum gravity at this order.

Contribution

It completes previous calculations by identifying the origin of divergences and demonstrating the finiteness of the cross section with bremsstrahlung, advancing understanding of quantum gravity's infrared properties.

Findings

Infrared divergences originate from the infrared sector.

Including bremsstrahlung diagrams renders the cross section finite.

The result is model independent and consistent with quantum gravity expectations.

Abstract

The quantum effective theory of general relativity, independent of the eventual full theory at high energy, expresses graviton-graviton scattering at one loop order O(E^4) with only one parameter, Newton's constant. Dunbar and Norridge have calculated the one loop amplitude using string based techniques. We complete the calculation by showing that the 1/(d-4) divergence which remains in their result comes from the infrared sector and that the cross section is finite and model independent when the usual bremsstrahlung diagrams are included.