Cosmic Acceleration Driven by Mirage Inhomogeneities

TL;DR

This paper proposes a cosmological model where inhomogeneities in a brane-world scenario lead to cosmic acceleration, potentially explaining the smallness of the cosmological constant and providing insights into dark matter and early universe acceleration.

Contribution

It introduces a novel inhomogeneous brane-world model that accounts for cosmic acceleration and the small cosmological constant through geometrical inhomogeneities.

Findings

The model exhibits an accelerating expansion with an effective cosmological constant inversely related to distance from the center.

Mirage-driven acceleration can serve as a dark matter component in the universe.

The model aligns with current observational constraints on inhomogeneities.

Abstract

A cosmological model based on an inhomogeneous D3-brane moving in an AdS_5 X S_5 bulk is introduced. Although there is no special points in the bulk, the brane Universe has a center and is isotropic around it. The model has an accelerating expansion and its effective cosmological constant is inversely proportional to the distance from the center, giving a possible geometrical origin for the smallness of a present-day cosmological constant. Besides, if our model is considered as an alternative of early time acceleration, it is shown that the early stage accelerating phase ends in a dust dominated FRW homogeneous Universe. Mirage-driven acceleration thus provides a dark matter component for the brane Universe final state. We finally show that the model fulfills the current constraints on inhomogeneities.