Large-scale magnetic fields from inflation due to a $CPT$-even Chern-Simons-like term with Kalb-Ramond and scalar fields

TL;DR

This paper explores how inflationary cosmology with a $CPT$-even Chern-Simons-like interaction involving Kalb-Ramond and scalar fields can generate large-scale magnetic fields, potentially explaining observed cosmic magnetism.

Contribution

It introduces a novel mechanism for magnetic field generation during inflation via a $CPT$-even dimension-six Chern-Simons-like term with dynamical fields.

Findings

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

The mechanism breaks conformal invariance to enable magnetic field generation.

Results are consistent with observed cosmic magnetic fields.

Abstract

We investigate the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the $CPT$-even dimension-six Chern-Simons-like effective interaction with a fermion current by taking account of the dynamical Kalb-Ramond and scalar fields in inflationary cosmology. It is explicitly demonstrated that the magnetic fields on 1Mpc scale with the field strength of $\sim 10^{-9}$G at the present time can be induced.