One loop photon-graviton mixing in an electromagnetic field: Part 1

TL;DR

This paper derives a compact, covariant integral representation for one-loop photon-graviton mixing amplitudes in a constant electromagnetic field, considering charged scalar or spinor particles, relevant for cosmology and astrophysics.

Contribution

It introduces a worldline formalism approach to compute the one-loop photon-graviton mixing amplitude in arbitrary constant electromagnetic fields.

Findings

Provides a two-parameter integral representation of the amplitude.

Valid for arbitrary photon energies and field strengths.

Uses a manifestly covariant calculation method.

Abstract

Photon-graviton mixing in an electromagnetic field is a process of potential interest for cosmology and astrophysics. At the tree level it has been studied by many authors. We consider the one-loop contribution to this amplitude involving a charged spin 0 or spin 1/2 particle in the loop and an arbitrary constant field. In the first part of this article, the worldline formalism is used to obtain a compact two-parameter integral representation for this amplitude, valid for arbitrary photon energies and background field strengths. The calculation is manifestly covariant througout.