Brane gas cosmology in M-theory: late time behavior

TL;DR

This paper explores the late-time evolution of a universe in M-theory with supergravity gas and wrapped 2-branes, revealing how brane configurations influence the expansion and hierarchy of spatial dimensions.

Contribution

It provides a detailed analysis of how brane wrapping numbers determine the power-law expansion and hierarchies of dimensions in M-theory cosmology.

Findings

Power-law growth of radii depending on brane wrapping numbers

Emergence of three large unwrapped dimensions from initial fluctuations

Recovery of Brandenberger-Vafa scenario with string winding configurations

Abstract

We investigate the late-time behavior of a universe containing a supergravity gas and wrapped 2-branes in the context of M-theory compactified on T^10. The supergravity gas tends to drive uniform expansion, while the branes impede the expansion of the directions about which they are wrapped. Assuming spatial homogeneity, we study the dynamics both numerically and analytically. At late times the radii obey power laws which are determined by the brane wrapping numbers, leading to interesting hierarchies of scale between the wrapped and unwrapped dimensions. The biggest hierarchy that could evolve from an initial thermal fluctuation produces three large unwrapped dimensions. We also study configurations corresponding to string winding, in which the M2-branes are all wrapped around the (small) 11th dimension, and show that this recovers the scenario discussed by Brandenberger and Vafa.