Dark energy cosmologies for codimension-two branes

TL;DR

This paper presents exact solutions for six-dimensional cosmologies with two branes, showing how internal space dynamics can lead to realistic late-time behaviors like quintessence or radiation domination, with implications for dark energy models.

Contribution

It introduces a family of exact, time-dependent solutions in six-dimensional brane-world models, connecting internal space evolution to observable cosmological phases.

Findings

Late-time cosmology can be quintessence-like or radiation dominated.

The solutions include a free cosmological constant as an integration constant.

Detailed analysis of relativistic fermions in the radiation-dominated phase.

Abstract

A six-dimensional universe with two branes in the "football-shaped" geometry leads to an almost realistic cosmology. We describe a family of exact solutions with time dependent characteristic size of internal space. After a short inflationary period the late cosmology is either of quintessence type or turns to a radiation dominated Friedmann universe where the cosmological constant appears as a free integration constant of the solution. The radiation dominated universe with relativistic fermions is analyzed in detail, including its dimensional reduction.