Is exponential gravity a viable description for the whole cosmological history?

TL;DR

This paper investigates exponential $F(R)$ gravity as a potential unified model for the entire cosmological history, including late-time acceleration and inflation, and finds it consistent with current observational data.

Contribution

It demonstrates that exponential $F(R)$ gravity can describe both late-time acceleration and inflation within a single framework, fitting observational constraints.

Findings

Exponential gravity models fit cosmological data as well as $\\Lambda$CDM.

The model can reproduce inflationary epoch consistent with Planck data.

Corrections to General Relativity are significant at cosmological scales.

Abstract

Here we analysed a particular type of $F(R)$ gravity, the so-called exponential gravity which includes an exponential function of the Ricci scalar in the action. Such term represents a correction to the usual Hilbert-Einstein action. By using Supernovae Ia, Barionic Acoustic Oscillations, Cosmic Microwave Background and $H(z)$ data, the free parameters of the model are well constrained. The results show that such corrections to General Relativity become important at cosmological scales and at late-times, providing an alternative to the dark energy problem. In addition, the fits do not determine any significant difference statistically with respect to the $\Lambda$CDM model. Finally, such model is extended to include the inflationary epoch in the same gravitational Lagrangian. As shown in the paper, the additional terms can reproduce the inflationary epoch and satisfy the constraints from Planck data.