Late-time cosmic acceleration: Dark gravity

TL;DR

This paper reviews the hypothesis that late-time cosmic acceleration is caused by infrared modifications to Einstein's General Relativity, discussing various modified gravity theories as potential explanations.

Contribution

It provides a comprehensive review of modified gravity theories as alternatives to dark energy for explaining cosmic acceleration.

Findings

Infra-red modifications can account for late-time acceleration.

Modified gravity theories offer viable alternatives to dark energy.

The paper summarizes key models and their implications.

Abstract

A central theme in cosmology is the perplexing fact that the Universe is undergoing an accelerating expansion. The latter, one of the most important and challenging current problems in cosmology, represents a new imbalance in the governing gravitational field equations. Several candidates, responsible for this expansion, have been proposed in the literature, in particular, dark energy models and modified gravity, amongst others. In this paper, we explore the possibility that the late-time cosmic acceleration is due to infra-red modifications of Einstein's theory of General Relativity, and review some of the modified theories of gravity that address this intriguing and exciting problem facing modern physics.