The thermal view of $f(R)$ cosmology

TL;DR

This paper introduces a thermal perspective on $f(R)$ gravity, analyzing how these theories evolve towards Einstein cosmology and applying the formalism to specific models like Starobinsky gravity.

Contribution

It develops a new thermal framework for scalar-tensor gravity and applies it to $f(R)$ theories, providing insights into their convergence to Einstein cosmology.

Findings

General $f(R)$ theories' convergence behavior analyzed

Power-law $f(R)$ models studied within the thermal framework

Starobinsky $f(R)$ gravity examined for cosmological convergence

Abstract

A new thermal view of scalar-tensor gravity, in which general relativity is the zero-temperature state of gravity, is applied to the specific subclass of $f(R)$ gravity theories and, specifically, to spatially homogeneous and isotropic universes. Within the limits of application of the new thermal formalism, results on the convergence to Einstein cosmology (or lack thereof) are first obtained for general $f(R)$ theories, and then illustrated with power-law and Starobinsky $f(R)$ gravity.