Moduli stabilization with string gas and fluxes

The question of how to stabilize all of the modulus fields coming from compactifications of string theory on internal manifolds is one of the outstanding challenges for string cosmology. Here, in the simple example of a toroidal compactification, we study the dynamics of the moduli fields corresponding to the size and shape of the torus along with the ambient flux. It is known that a string gas containing states with non-vanishing winding and momentum numbers can stabilize the volume modulus. In this paper we show that a gas of string modes which becomes massless at the self-dual radius can stabilize the shape moduli.