Electromagnetic Properties of the Early Universe

TL;DR

This paper investigates the generation of magnetic fields in the early universe by solving Maxwell's equations with a novel approach that treats electrons and photons separately, revealing second-order effects in magnetic field creation.

Contribution

It introduces a new method that considers electrons and photons as separate components, providing a more detailed analysis of magnetic field generation from density fluctuations.

Findings

Magnetic field generation occurs only at second order in perturbation theory.

Electrons and photons are treated as separate components, unlike previous models.

The evolution of charge density, current, and electromagnetic fields is explicitly solved.

Abstract

Detailed physical processes of magnetic field generation from density fluctuations in the pre-recombination era are studied. Solving Maxwell equations and the generalized Ohm's law, the evolutions of the net charge density, the electric current and the electromagnetic field are solved. Unlike most of previous works, we treat electrons and photons as separate components under the assumption of tight coupling. We find that generation of the magnetic field due to density fluctuations takes place only from the second order of both perturbation theory and the tight coupling approximation.