Primordial magnetic fields at preheating

TL;DR

This paper uses lattice simulations to study the generation of large-scale magnetic fields during the early universe's electroweak transition, highlighting magnetic string formation and turbulent scalar field behavior.

Contribution

It introduces a lattice-based analysis of magnetic field generation during preheating, proposing magnetic strings from EW sphaleron-like configurations as a novel mechanism.

Findings

Magnetic fields form as magnetic strings during bubble collisions.

Magnetic strings may originate from aligned magnetic dipoles of sphaleron-like configurations.

Photon thermalization and scalar field turbulence occur post-preheating.

Abstract

Using lattice techniques we investigate the generation of long range cosmological magnetic fields during a cold electroweak transition. We will show how magnetic fields arise, during bubble collisions, in the form of magnetic strings. We conjecture that these magnetic strings originate from the alignment of magnetic dipoles associated with EW sphaleron-like configurations. We also discuss the early thermalisation of photons and the turbulent behaviour of the scalar fields after tachyonic preheating.