Power spectrum of large-scale magnetic fields from Gravitoelectromagnetic inflation with a decaying cosmological parameter

TL;DR

This paper explores the origin and evolution of primordial magnetic fields during inflation with a decaying cosmological parameter, using a 5D geometric approach that naturally breaks conformal invariance.

Contribution

It introduces a novel formalism based on 5D Riemann-flat metrics to study magnetic field spectra without relying on the Feynman gauge, accounting for a time-varying cosmological parameter.

Findings

Derived power spectra for large-scale magnetic fields

Analyzed inflaton field fluctuations during inflation

Demonstrated a naturally non-conformally invariant formalism

Abstract

Introducing a variable cosmological parameter $\Lambda (t)$ in a geometrical manner from a 5D Riemann-flat metric, we investigate the origin and evolution of primordial magnetic fields in the early universe, when the expansion is governed by a cosmological parameter $\Lambda (t)$ that decreases with time. Using the gravitoelectromagnetic inflationary formalism, but without the Feynman gauge, we obtain the power of spectrums for large-scale magnetic fields and the inflaton field fluctuations during inflation. A very important fact is that our formalism is {\em naturally non-conformally invariant}.