Scale-invariance, dynamically induced Planck scale and inflation in the Palatini formulation

TL;DR

This paper introduces two scale-invariant inflation models within the Palatini gravity framework, where quadratic curvature terms dynamically generate the Planck scale and reduce the tensor-to-scalar ratio, offering new insights into early universe cosmology.

Contribution

The paper proposes novel scale-invariant inflation models in Palatini gravity with quadratic curvature terms that dynamically induce the Planck scale and lower the tensor-to-scalar ratio.

Findings

Planck scale generated dynamically from scalar fields

Reduced tensor-to-scalar ratio in the models

Consistent inflationary predictions within Palatini formulation

Abstract

We present two scale invariant models of inflation in which the addition of quadratic in curvature terms in the usual Einstein-Hilbert action, in the context of Palatini formulation of gravity, manages to reduce the value of the tensor-to-scalar ratio. In both models the Planck scale is dynamically generated via the vacuum expectation value of the scalar fields.