Accelerated expansion in modified gravity with a Yukawa-like term

TL;DR

This paper explores a modified gravity model with a Yukawa-like term, demonstrating its potential to explain the universe's accelerated expansion and analyzing its implications in different formulations and limits.

Contribution

It introduces a modified gravity model with a Yukawa-like term in the Palatini formulation, showing its ability to account for cosmic acceleration and connecting it to standard cosmology.

Findings

Yukawa term explains exponential accelerated expansion in Palatini formulation.

Scalar-tensor formulation predicts power-law late-time acceleration.

Model reduces to standard Friedmann cosmology under certain limits.

Abstract

We discuss the Palatini formulation of modified gravity including a Yukawa-like term. It is shown that in this formulation, the Yukawa term offers an explanation for the current exponential accelerated expansion of the universe and reduces to the standard Friedmann cosmology in the appropriate limit. We then discuss the scalar-tensor formulation of the model as a metric theory and show that the Yukawa term predicts a power-law acceleration at late-times. The Newtonian limit of the theory is also discussed in context of the Palatini formalism.