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 …

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 …

A bstract We present all scalar-tensor Lagrangians that are cubic in second derivatives of a
scalar field, and that are degenerate, hence avoiding Ostrogradsky instabilities. Thanks to …

We introduce the Vainshtein mechanism which plays a crucial role in massive gravities, as
well as in related theories such as Galileons and their extensions. This mechanism, also …

A bstract We study the background cosmology of the ghost-free, bimetric theory of gravity.
We perform an extensive statistical analysis of the model using both frequentist and …

We construct a fully covariant theory of massive gravity which does not require the
introduction of an external reference metric, and overcomes the usual problems of massive …

We present a formulation of ghost-free massive gravity with flat reference metric that exhibits
the full nonlinear constraint algebraically, in a way that can be directly implemented for …

We study the cosmological consequences of a recently proposed nonlocal modification of
general relativity, obtained by adding a term m 2 R□− 2 R to the Einstein-Hilbert action. The …

A bstract We provide a full analysis of ghost free higher derivative field theories with coupled
degrees of freedom. Assuming the absence of gauge symmetries, we derive the degeneracy …

We study static spherically symmetric solutions of massive bigravity theory, free from the
Boulware-Deser ghost. We show the recovery of general relativity via the Vainshtein …