Magnetogenesis in bouncing cosmology

TL;DR

This paper demonstrates that nonsingular bounce cosmology can generate large primordial magnetic fields during contraction, avoiding common issues and satisfying observational constraints within certain parameter ranges.

Contribution

It introduces a mechanism for magnetogenesis in bounce cosmology that circumvents strong coupling and backreaction problems, providing new theoretical constraints and viable parameter space.

Findings

Primordial magnetic fields can be generated during contraction without strong coupling issues.

Theoretical constraints relate bounce energy scale to magnetic field spectrum.

Parameter space exists where magnetogenesis is consistent with observations.

Abstract

We consider the process of magnetogenesis in the context of nonsingular bounce cosmology. We show that large primordial magnetic fields can be generated during contraction without encountering strong coupling and backreaction issues. The fields may seed large-scale magnetic fields with observationally interesting strengths. This result leads to a theoretical constraint on the relation of the energy scale of the bounce cosmology to the number of effective e-folding of the contracting phase in the case of scale invariance for the power spectrum of primordial magnetic fields. We show that this constraint can be satisfied in a sizable region of the parameter space for the nonsingular bounce cosmology.