Structure formation on the brane: A mimicry

TL;DR

This paper explores how braneworld cosmology with bulk matter, specifically a Weyl fluid, can explain structure formation and mimic dark matter, altering perturbation equations and potentially accounting for observed inhomogeneities.

Contribution

It demonstrates that the Weyl fluid in braneworld models can drive structure formation and mimic dark matter, providing a novel explanation within this cosmological framework.

Findings

Weyl fluid dominates over matter at late times.

Perturbation equations are significantly altered by the Weyl fluid.

The Weyl fluid can effectively mimic dark matter.

Abstract

We show how braneworld cosmology with bulk matter can explain structure formation. In this scenario, the nonlocal corrections to the Friedmann equations supply a Weyl fluid that can dominate over matter at late times due to the energy exchange between the brane and the bulk. We demonstrate that the presence of the Weyl fluid radically changes the perturbation equations, which can take care of the fluctuations required to account for the large amount of inhomogeneities observed in the local universe. Further, we show how this Weyl fluid can mimic dark matter. We also investigate the bulk geometry responsible for the scenario.