Primordial magnetic fields and gravitational baryogenesis in nonlinear electrodynamics

TL;DR

This paper explores how nonlinear electrodynamics can amplify primordial magnetic fields and facilitate gravitational baryogenesis, providing constraints based on observed cosmic magnetic fields and baryon asymmetry.

Contribution

It investigates the effects of nonlinear electrodynamics on primordial magnetic field amplification and baryogenesis, deriving constraints from observational data.

Findings

Constraints on nonlinear electrodynamics parameters from magnetic field observations.

Constraints on nonlinear electrodynamics parameters from baryon asymmetry.

Solutions to gauge invariant wave equations in different cosmic eras.

Abstract

The amplification of the primordial magnetic fields and the gravitational baryogenesis, a mechanism that allows to generate the baryon asymmetry in the Universe by means of the coupling between the Ricci scalar curvature and the baryon current, are reviewed in the framework of the nonlinear electrodynamics. To study the amplification of the primordial magnetic field strength, we write down the gauge invariant wave equations and then solve them (in the long wavelength approximation) for three different eras of the Universe: de Sitter, the reheating and the radiation dominated era. Constraints on parameters entering the nonlinear electrodynamics are obtained by using the amplitude of the observed galactic magnetic fields and the baryon asymmetry, which are characterized by the dimensionless parameters $r\sim 10^{-37}$ and $\eta_B\lesssim 9\times 10^{-11}$, respectively.