Primordial Magnetic Fields that Last?

TL;DR

This paper investigates the evolution of primordial magnetic fields generated near the electroweak phase transition, focusing on their potential to grow in correlation length and survive until galaxy formation.

Contribution

It analyzes a specific pseudoscalar-driven primordial magnetic field scenario and discusses its potential to produce large, long-lasting magnetic fields in the early universe.

Findings

The scenario has attractive features for magnetic field generation.

Uncertainty remains whether such fields can survive until late times.

Further work is needed to determine the field's evolution and survival.

Abstract

The magnetic fields we observe in galaxies today may have their origins in the very early universe. While a number of mechanisms have been proposed which lead to an appreciable field amplitude at early times, the subsequent evolution of the field is of crucial importance, especially whether the correlation length of the field can grow as large as the size of a protogalaxy. This talk is a report on work in progress, in which we consider the fate of one specific primordial field scenario, driven by pseudoscalar effects near the electroweak phase transition. We argue that such a scenario has a number of attractive features, although it is still uncertain whether a field of appropriate size can survive until late times.