A number of challenges to the standard Λ CDM model have been emerging during the past
few years as the accuracy of cosmological observations improves. In this review we discuss …

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 …

Over the past decade, f (R) theories have been extensively studied as one of the simplest
modifications to General Relativity. In this article we review various applications of f (R) …

The status of experimental tests of general relativity and of theoretical frameworks for
analyzing them is reviewed and updated. Einstein's equivalence principle (EEP) is well …

After a decade and a half of research motivated by the accelerating universe, theory and
experiment have reached a certain level of maturity. The development of theoretical models …

This article is intended to review the recent developments in the Horndeski theory and its
generalization, which provide us with a systematic understanding of scalar–tensor theories …

We review recent progress in massive gravity. We start by showing how different theories of
massive gravity emerge from a higher-dimensional theory of general relativity, leading to the …

In the Dvali-Gabadadze-Porrati (DGP) model, the “self-accelerating” solution is plagued by a
ghost instability, which makes the solution untenable. This fact, as well as all interesting …

Abstract Euclid is a European Space Agency medium-class mission selected for launch in
2020 within the cosmic vision 2015–2025 program. The main goal of Euclid is to understand …

We determine the most general scalar field theories which have an action that depends on
derivatives of order two or less, and have equations of motion that stay second order and …