Predictions of dynamically emerging brane inflation models

Abstract

We confront the recent proposal of emerging brane inflation with $\mathrm{WMAP}3+\mathrm{SDSS}$, finding a scalar spectral index of ${n}_{s}={0.9659}_{\ensuremath{-}0.0052}^{+0.0049}$ in excellent agreement with observations. The proposal incorporates a preceding phase of isotropic, nonaccelerated expansion in all dimensions, providing suitable initial conditions for inflation. Additional observational constraints on the parameters of the model provide an estimate of the string scale. A graceful exit to inflation and stabilization of extra dimensions is achieved via a string gas. The resulting preheating phase shows some novel features due to a redshifting potential, comparable to effects due to the expansion of the universe itself. However, the model at hand suffers from either a potential overproduction of relics after inflation or insufficient stabilization at late times.