Occupy magnetogenesis

Abstract

The occupation number of a field is a sound discriminator between classical and quantum regimes. In this pamphlet we give an overview of what we can learn about inflationary magnetogenesis just by looking at the occupation numbers of the classical magnetic fields observed today, and those of the quantum electromagnetic field during inflation. The sole occupation number behaviour dictates that for a pure Maxwell theory in de Sitter space it appears impossible to match the two epochs.