We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of the… (More)

Recently, an interesting scalar field, ‘‘Galileon,’’ theory [1], inspired by the decoupling limit of the DvaliGabadadze-Porrati (DGP) model [2] and its cosmological consequences [3], was introduced.… (More)

The gravitational radiation from point particle binaries is computed at the third post-Newtonian (3PN) approximation of general relativity. Three previously introduced ambiguity parameters, coming… (More)

Dimensional regularization is applied to the computation of the gravitational wave field generated by compact binaries at the third post-Newtonian (3PN) approximation. We generalize the wave… (More)

We show that the current bounds on the time variation of the Newton constant G can put severe constraints on many interesting scalar-tensor theories which possess a shift symmetry and a nonminimal… (More)

We show that scalar, 0-form, Galileon actions—models whose field equations contain only second derivatives—can be generalized to arbitrary even p-forms. More generally, they need not even depend on a… (More)

Scalar-tensor theories are the best motivated alternatives to general relativity and provide a mathematically consistent framework to test the various observable predictions. They can involve three… (More)

Modified Newtonian dynamics (MOND) is a possible way to explain the flat galaxy rotation curves without invoking the existence of dark matter. It is however quite difficult to predict such a… (More)

Although general relativity (GR) passes all present experi m ntal tests with flying colors, it remains important to study alternative the ori s of gravity for several theoretical and phenomenological… (More)

This talk reviews the constraints imposed by binary-pulsar data on gravity theories, focusing on " tensor-scalar " ones which are the best motivated alternatives to general relativity. We recall that… (More)