Brane-world cosmology of modulus stabilization with a bulk scalar field - art. no. 023505

We point out that the potential of Goldberger and Wise for stabilizing the distance between two 3-branes, separated from each other along an extra dim ension with a warp factor, has a metastable minimum when the branes are inf initely separated. The classical evolution of the radion (brane separation) will place it in this false minimum for generic initial conditions. In par ticular, inflation could do this if the expansion rate is sufficiently larg e. We present a simplified version of the Goldberger-Wise mechanism in whic h the radion potential can be computed exactly, and we calculate the rate o f thermal transitions to the true minimum, showing that model parameters ca n be chosen to ensure that the universe reaches the desired final state. Fi niteness of bulk scalar field brane potentials can have an important impact on the nucleation rate; and it can also significantly increase the predict ed mass of the radion.