Cosmological Magnetic Fields from Inflation and Backreaction

TL;DR

This paper investigates the backreaction effect in inflationary magnetogenesis, revealing that inflation persists despite backreaction, but primordial magnetic field generation is notably suppressed.

Contribution

It provides a detailed analysis of backreaction in inflationary magnetogenesis, challenging the assumption that backreaction halts inflation and quantifying its suppressive impact on magnetic field creation.

Findings

Inflation continues even after backreaction begins.

Primordial magnetic field production is significantly suppressed.

Backreaction does not necessarily terminate inflation.

Abstract

We study the backreaction problem in a mechanism of magnetogenesis from inflation. In usual analysis, it has been assumed that the backreaction due to electromagnetic fields spoils inflation once it becomes important. However, there exists no justification for this assumption. Hence, we analyze magnetogenesis from inflation by taking into account the backreaction. On the contrary to the naive expectation, we show that inflation still continues even after the backreaction begins to work. Nevertheless, it turns out that creation of primordial magnetic fields is significantly suppressed due to the backreaction.