Predictions of Dynamically Emerging Brane Inflation Models

TL;DR

This paper evaluates the Emerging Brane Inflation model against observational data, confirming its spectral index prediction and exploring its initial conditions, stabilization mechanisms, and post-inflation relic production issues.

Contribution

It provides observational constraints on the model's parameters, estimates the string scale, and discusses novel pre-heating features and stabilization challenges.

Findings

Spectral index matches observations ($n_s=0.9659$).

Initial conditions are set by a non-accelerated phase.

Model faces relic over-production or stabilization issues.

Abstract

We confront the recent proposal of Emerging Brane Inflation with WMAP3+SDSS, finding a scalar spectral index of $n_s=0.9659^{+0.0049}_{-0.0052}$ in excellent agreement with observations. The proposal incorporates a preceding phase of isotropic, non accelerated 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 pre-heating 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 over-production of relics after inflation or insufficient stabilization at late times.