Equation-of-state formalism for dark energy models on the brane and the future of brane universes

TL;DR

This paper explores various future evolutions of brane dark energy cosmologies, highlighting how brane tension influences the universe's fate, including phenomena like Little Rip and different singularities, with deviations from standard cosmology.

Contribution

It introduces a formalism for equation-of-state in brane dark energy models and analyzes how brane tension affects future cosmic evolution and singularity types.

Findings

Little Rip occurs faster on the brane than in standard cosmology.

Brane tension causes deviations in the effective cosmological constant.

Inertial forces from acceleration can greatly exceed those in ordinary models.

Abstract

Brane dark energy cosmologies, leading to various possible evolutions of our universe, are investigated. The discussion shows that while all these models can be made arbitrarily close to the standard $\Lambda$CDM cosmology at present, their future evolutions can be very different, even diverge with time in a number of ways. This includes asymptotic de-Sitter evolution, Little Rip with dissolution of bound structures, and various possible singularities, as the Big Rip, a sudden future singularity (Type II), and Type III and Type IV cases. Specifically, some interesting effects coming from the brane tension are investigated. It is shown, in particular, that the Little Rip occurs faster on the brane model than in usual FRW cosmology. And in the asymptotic de-Sitter regime the influence of the brane tension leads to a deviation of the value of the effective cosmological constant from that corresponding to ordinary dark energy. As a consequence, the value of the inertial force from the accelerating expansion can greatly exceed the corresponding inertial force in ordinary cosmological models.