Primordial magnetogenesis in a bouncing model with dark energy

TL;DR

This paper explores how different electromagnetic coupling scenarios in a quantum bouncing cosmology can generate primordial magnetic fields, finding that only a Gaussian coupling effectively produces cosmologically relevant magnetic fields.

Contribution

It introduces a detailed analysis of primordial magnetogenesis in a quantum bouncing model with various electromagnetic couplings, highlighting the unique effectiveness of Gaussian coupling.

Findings

Gaussian coupling can generate cosmologically relevant magnetic fields

No coupling or Cauchy coupling are ineffective for primordial magnetogenesis

Scalar field behaves as matter, stiff matter, and dark energy in different phases

Abstract

We investigate primordial magnetogenesis within a quantum bouncing model driven by a scalar field, focusing on various non-minimal couplings between the electromagnetic field and the scalar field. We test three cases: no coupling, a Cauchy coupling with gradual decay, and a Gaussian coupling with rapid fall-off. By exploring these scenarios, we assess a wide range of coupling strengths across different scales. The scalar field, with an exponential potential, behaves as pressureless matter in the asymptotic past of the contracting phase, as stiff matter around the bounce, and as dark energy during the expanding phase. Our findings reveal that, among the tested cases, only the Gaussian coupling can explain the generation of primordial magnetic fields on cosmological scales.