Brane Gas Cosmology, M-theory and Little String Theory

TL;DR

This work extends Brane Gas Cosmology to the M-theory regime by incorporating $M2$ and $M5$ branes and their intersections. While BV-like dynamics in a pure membrane gas would generically favor decompactification of $6$ dimensions, including string-like $M2$–$M5$ intersections can drive a dynamical transition to a $3+1$-dimensional spacetime, aided by $G$-flux stabilization. Through holography, the thermodynamics of $(2,0)$ Little Strings on NS5 branes (arising from M5–M2 intersections) yields a BV-consistent equation of state that selects a four-dimensional universe with a hierarchical growth of dimensions, in agreement with Kabat’s anisotropic wrapping results. The paper thus provides a coherent 11D picture linking brane gas dynamics, fluxes, and holographic Little Strings as a mechanism for late-time decompactification, while outlining open questions about holographic unwinding and loitering/inflation scenarios for solving the brane problem.

Abstract

We generalize the Brane Gas Cosmological Scenario to M-theory degrees of freedom, namely $M5$ and $M2$ branes. Without brane intersections, the Brandenberger Vafa(BV) arguments applied to M-theory degrees of freedom generically predict a large 6 dimensional spacetime. We show that intersections of $M5$ and $M2$ branes can instead lead to a large 4 dimensional spacetime. One dimensional intersections in 11D is related to (2,0) little strings (LST) on NS5 branes in type IIA. The gas regime of membranes in M-theory corresponds to the thermodynamics of LST obtained from holography. We propose a mechanism whereby LST living on the worldvolume of NS5 (M5)-branes wrapping a five dimensional torus, annihilate most efficiently in 3+1 dimensions leading to a large 3+1 dimensional spacetime. We also show that this picture is consistent with the gas approximation in M-theory.