Generation of large-scale magnetic fields from inflation in teleparallelism

TL;DR

This paper investigates how large-scale magnetic fields can be generated during inflation within teleparallel gravity, showing that a non-minimal coupling can produce magnetic fields of observable strength today.

Contribution

It introduces a novel mechanism for magnetic field generation during inflation using teleparallelism with a power-law coupling between torsion and electromagnetic fields.

Findings

Magnetic fields of ~10^{-9} G can be generated on 1 Mpc scales.

The model demonstrates the viability of inflationary magnetogenesis in teleparallel gravity.

A power-law coupling effectively breaks conformal invariance during inflation.

Abstract

We explore the generation of large-scale magnetic fields from inflation in teleparallelism, in which the gravitational theory is described by the torsion scalar instead of the scalar curvature in general relativity. In particular, we examine the case that the conformal invariance of the electromagnetic field during inflation is broken by a non-minimal gravitational coupling between the torsion scalar and the electromagnetic field. It is shown that for a power-law type coupling, the magnetic field on 1 Mpc scale with its strength of $\sim 10^{-9}$ G at the present time can be generated.