Modified Gravity and Cosmology

TL;DR

This comprehensive review surveys recent advances in modified gravity theories and their implications for cosmology, covering a wide range of models and frameworks motivated by observational tests of fundamental physics.

Contribution

It provides an extensive, up-to-date overview of various modified gravity theories, their cosmological consequences, and formalism for constraining deviations from General Relativity.

Findings

Various modified gravity models have been developed and analyzed.

Progress in observational cosmology enables precision tests of these theories.

A formalism for constraining deviations from General Relativity has been reviewed.

Abstract

In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, Scalar-Tensor, Einstein-Aether, and Bimetric theories, as well as TeVeS, f(R), general higher-order theories, Horava-Lifschitz gravity, Galileons, Ghost Condensates, and models of extra dimensions including Kaluza-Klein, Randall-Sundrum, DGP, and higher co-dimension braneworlds. We also review attempts to construct a Parameterised Post-Friedmannian formalism, that can be used to constrain deviations from General Relativity in cosmology, and that is suitable for comparison with data on the largest scales. These subjects have been intensively studied over the past decade, largely motivated by rapid progress in the field of observational cosmology that now allows, for the first time, precision tests of fundamental physics on the scale of the observable Universe. The purpose of this review is to provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a self-contained, comprehensive and up-to-date introduction to the subject as a whole.