Metric-torsion preheating: cosmic dynamo mechanism?

TL;DR

This paper explores how metric-torsion effects during preheating could generate seed magnetic fields in the universe, which are weaker than previous models but potentially sufficient for galactic dynamo seeding.

Contribution

It introduces a novel analysis of metric-torsion preheating perturbations and estimates the resulting seed magnetic field strength in a torsion-inclusive universe.

Findings

Seed magnetic field of ~10^{-37} Gauss from torsion preheating.

Magnetic field weaker than pure metric preheating but still potentially seeding galactic dynamo.

Highlights importance of torsion effects in early universe magnetogenesis.

Abstract

Earlier Bassett et al [Phys Rev D 63 (2001) 023506] investigated the amplification of large scale magnetic fields during preheating and inflation in several different models. They argued that in the presence of conductivity resonance effect is weakened. From a dynamo equation in spacetimes endowed with torsion recently derived by Garcia de Andrade [Phys Lett B 711: 143 (2012)] it is shown that a in a universe with pure torsion in Minkowski spacetime the cosmological magnetic field is enhanced by ohmic or non-conductivity effect, which shows that the metric-torsion effects is worth while of being studied. In this paper we investigated the metric-torsion preheating perturbation, which leads to the seed cosmological magnetic field in the universe with torsion is of the order of $B_{seed}\sim{10^{-37}Gauss}$ which is several orders of magnitude weaker than the decoupling value obtained from pure metric preheating of $10^{-15}Gauss$. Despite of the weakness of the magnetic field this seed field may seed the galactic dynamo.