Strings, Fivebranes and an Expanding Universe

TL;DR

This paper demonstrates that velocity-dependent forces between fundamental strings and fivebranes can lead to an accelerating universe, extending previous results to more complex brane backgrounds and suggesting a general mechanism for cosmic acceleration.

Contribution

It generalizes earlier findings by showing that accelerating universe solutions also occur in fivebrane backgrounds and potentially in broader p-brane models.

Findings

Accelerating universe solutions are valid in fivebrane backgrounds.

Velocity-dependent forces induce cosmic acceleration.

The mechanism likely applies to general p-brane models.

Abstract

It was recently shown that velocity-dependent forces between parallel fundamental strings moving apart in a $D-$dimensional spacetime implied an accelerating expanding universe in $D-1$-dimensional space-time. Exact solutions were obtained for the early time expansion in $D=5,6$. Here we show that this result also holds for fundamental strings in the background of a fivebrane, and argue that the feature of an accelerating universe would hold for more general $p$-brane-seeded models.