Effective field theories and inflationary magnetogenesis

TL;DR

This paper develops a comprehensive effective field theory framework for inflationary magnetogenesis, including all relevant covariant terms, and analyzes how these influence gauge field spectra during inflation.

Contribution

It introduces a general method to include all covariant four-derivative terms in the effective action for inflationary magnetogenesis, accounting for inflaton-dependent couplings.

Findings

Higher derivatives induce asymmetry between hypermagnetic and hyperelectric susceptibilities.

The method applies to generic inflationary models and special scenarios with extra symmetries.

Results show the impact of higher-order terms on gauge power spectra during inflation.

Abstract

The effective approach is applied to the analysis of inflationary magnetogenesis. Rather than assuming a particular underlying description, all the generally covariant terms potentially appearing with four space-time derivatives in the effective action have been included and weighted by inflaton-dependent couplings. The higher derivatives are suppressed by the negative powers of a typical mass scale whose specific values ultimately depend on the tensor to scalar ratio. During a quasi-de Sitter stage the corresponding corrections always lead to an asymmetry between the hypermagnetic and the hyperelectric susceptibilities. After presenting a general method for the estimate of the gauge power spectra, the obtained results are illustrated for generic models and also in the case of some non-generic scenarios where either the inflaton has some extra symmetry or the higher-order terms are potentially dominant.