Cosmological evolution in a brane-universe

TL;DR

This paper reviews how brane-world models with extra dimensions modify the universe's expansion laws and explores their implications for cosmological observations and perturbations.

Contribution

It summarizes the cosmological consequences of brane-world models, focusing on modifications to Friedmann laws and potential observational signatures.

Findings

Modified Friedmann equations in brane cosmology

Implications for cosmological perturbations

Potential observational signatures of extra dimensions

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.