Reheating with effective potentials

Abstract

We consider reheating for a charged inflaton which is minimally coupled toelectromagnetism. The evolution of such an inflaton induces a time-dependentmass for the photon. We show how the massive photon propagator can beexpressed as a spatial Fourier mode sum involving three different sorts ofmode functions, just like the constant mass case. We develop accurateanalytic approximations for these mode functions, and use them to approximatethe effective force exerted on the inflaton 0-mode. This effective forceallows one to simply compute the evolution of the inflaton 0-mode and tofollow the progress of reheating.