Gauge invariant fluctuations of the metric during inflation from new scalar-tensor Weyl-Integrable gravity model

TL;DR

This paper explores gauge-invariant scalar metric fluctuations during inflation within a novel scalar-tensor Weyl-Integrable gravity framework, revealing the Weyl scalar as a geometrical inflaton and analyzing power-law inflation spectra.

Contribution

It introduces a non-perturbative formalism for inflationary fluctuations in Weyl-Integrable scalar-tensor gravity, highlighting the geometric origin of the inflaton field.

Findings

Weyl scalar field can act as the inflaton.

Power law inflation achieves quasi-scale invariance for specific parameters.

The formalism provides a geometric perspective on inflationary fluctuations.

Abstract

We investigate gauge invariant scalar fluctuations of the metric during inflation in a non-perturbative formalism in the framework of a recently introduced scalar-tensor theory of gravity formulated on a Weyl-Integrable geometry. We found that the Weyl scalar field can play the role of the inflaton field in this theory. As an application we study the case of a power law inflation. In this case the quasi-scale invariance of the spectrum for scalar fluctuations of the metric is achieved for determined values of the $\omega$ parameter of the scalar-tensor theory. In our formalism the physical inflaton field has a geometrical origin.