Mirage Cosmology

TL;DR

This paper explores how a brane universe moving in higher-dimensional space can mimic matter-driven cosmology, revealing novel mirage energy effects and addressing the initial singularity problem.

Contribution

It introduces a model where brane motion induces cosmological evolution with unique mirage energy densities, including superluminal and energy condition-violating types.

Findings

Mirage energy densities can drive expansion similar to matter.

Some mirage energies exhibit superluminal properties.

The initial singularity problem is naturally resolved.

Abstract

A brane universe moving in a curved higher dimensional bulk space is considered. The motion induces a cosmological evolution on the universe brane that is indistiguishable from a similar one induced by matter density on the brane. The phenomenological implications of such an idea are discussed. Various mirage energy densities are found, corresponding to dilute matter driving the cosmological expansion, many having superluminal properties $|w|>1$ or violating the positive energy condition. It is shown that energy density due to the world-volume fields is nicely incorporated into the picture. It is also pointed out that the initial singularity problem is naturally resolved in this context.