Non-Riemannian Volume Elements Dynamically Generate Inflation

TL;DR

This paper proposes a modified gravity model using non-Riemannian volume elements that naturally generates an inflationary scalar potential, aligning with observational data without introducing matter fields explicitly.

Contribution

It introduces a novel inflationary model based solely on modified gravity with dynamically generated scalar fields and potentials, extending the Starobinsky model.

Findings

Dynamically generates a scalar potential with a flat region and stable minimum.

Predicts scalar spectral index and tensor-to-scalar ratio consistent with observations.

Generalizes the classic Starobinsky inflationary potential.

Abstract

Our primary objective is the formulation of a plausible cosmological inflationary model entirely in terms of a pure modified gravity without any a priori matter couplings within the formalism of non-Riemannian spacetime volume elements. The non-Riemannian volume elements dynamically create in the physical Einstein frame a canonical scalar matter field and produce a non-trivial inflationary scalar potential with a large flat region and a low-lying stable minimum corresponding to the late universe stage. This dynamically generated inflationary potential is a substantial generalization of the classic Starobinsky potential. Our model predicts scalar power spectral index and tensor to scalar ratio in accordance with the available observational data.