Extra dimensions, warped compactifications and cosmic acceleration

TL;DR

This paper presents explicit cosmological solutions with an inflating brane in higher-dimensional spacetimes, showing that accelerated expansion can occur without violating energy conditions, and highlighting the role of brane tension induced by curvature.

Contribution

It provides new explicit solutions for inflating branes in five- and ten-dimensional bulk spacetimes, demonstrating acceleration without requiring a bulk cosmological constant.

Findings

Accelerated expansion occurs with nonzero brane tension.

Inflationary cosmology is possible without violating null energy conditions.

Brane tension is induced by curvature, not bulk cosmological terms.

Abstract

We report on explicit cosmological solutions within the framework of an inflating de Sitter brane embedded in five- and ten-dimensional bulk spacetimes. In the specific example we study the brane tension is induced by the curvature related to the expansion of a physical 3+1 spacetime rather than by a bulk cosmological term. In a generic situation with nonzero brane tension, the expansion of the universe accelerates eventually. We also show that inflationary cosmology is possible for a wide class of metrics without violating four- and higher-dimensional null energy condition.