Gravitoelectromagnetic inflation and seeds of cosmic magnetic fields from geometrical Weyl-invariant scalar-tensor theory of gravity

TL;DR

This paper explores a Weyl-invariant scalar-tensor gravity theory to explain the origin of cosmic magnetic fields and inflation, deriving scale-invariant spectra consistent with observations.

Contribution

It introduces a geometrical approach linking electromagnetic and inflaton fields to space-time geometry, producing scale-invariant spectra for magnetic fields and quantum fluctuations.

Findings

Generated seed magnetic fields of up to 10^9 gauss.

Obtained a Harrison-Zeldovich power spectrum for inflaton fluctuations.

Produced nearly scale-invariant electromagnetic spectra during inflation.

Abstract

We investigate cosmological inflationary scenarios from a gravitoelectromagnetic theory. Our work is formulated in the light of a recently introduced geometrical Weyl-Invariant scalar-tensor theory of gravity, where the nature of both the electromagnetic potential and the inflaton field is attributed to the space-time geometry. We obtain a Harrison-Zeldovich power spectrum for quantum fluctuations of the inflaton field. In our model the electromagnetic fields have also a nearly scale invariant power spectrum for a power-law inflation. We found that the the seed magnetic fields have a nearly scale invariant power spectrum and generate in the present times cosmic magnetic fields of the order $\lesssim 10^{9}$ gauss, in good agreement with CMB observations.