Photon mass from inflation

TL;DR

Vacuum polarization from massless scalar electrodynamics in de Sitter inflation exhibits a 3+1 dimensional analog of the Schwinger mechanism in which a photon mass is dynamically generated.

Abstract

We consider vacuum polarization from massless scalar electrodynamics in de Sitter inflation. The theory exhibits a 3+1 dimensional analogue of the Schwinger mechanism in which a photon mass is dynamically generated. The mechanism is generic for light scalar fields that couple minimally to gravity. The non-vanishing of the photon mass during inflation may result in magnetic fields on cosmological scales.

Figures (2)

• Figure 1: The one-loop diagrams contributing to the photon self-energy.
• Figure 2: Evolution of the physical scales in de Sitter inflation.