Cosmological evolution in a brane-universe

Abstract

The idea of extra-dimensions has recently gone through a renewal with the hypothesis, suggested by recent developments in string theory, that ordinary matter is confined to a sub-space, called brane, embedded in a higher dimensional spacetime. I summarize here some consequences in cosmology of this type of models. The most remarkable aspect is that the Friedmann laws, which govern the expansion of the Universe, are modified. An important direction of research is the study of cosmological perturbations and the possible signature of extra-dimensions in cosmological observations.