Eikonal Quantum Gravity and Planckian Scattering

TL;DR

This paper compares different high-energy quantum gravity scattering approaches using the eikonal approximation, clarifying their equivalences and the origin of scattering amplitudes from linearized gravity.

Contribution

It demonstrates the equivalence of the eikonal approximation with semiclassical and topological approaches in the massless limit, clarifying the origin of scattering amplitudes in quantum gravity.

Findings

Eikonal approximation matches semiclassical and topological results in the massless limit.

Scattering amplitude arises solely from linearized gravitational interaction.

Poles in the scattering amplitude are clarified in the context of these approaches.

Abstract

Various approaches to high energy forward scattering in quantum gravity are compared using the eikonal approximation. The massless limit of the eikonal is shown to be equivalent to other approximations for the same process, specifically the semiclassical calculation due to G. 't Hooft and the topological field theory due to H. and E. Verlinde. This comparison clarifies these previous results, as it is seen that the amplitude arises purely from a linearised gravitational interaction. The interpretation of poles in the scattering amplitude is also clarified.