Non-Gaussianity and Hybrid potentials

Series: 
The London Relativity and Cosmology Seminar
Speaker: 
Stefano Orani (Imperial)
Date: 
January 16th, 2013 at 16:30
Room: 
Maths 103
Abstract: 

I will discuss how the hybrid potential can lead to observationally compatible predictions in a regime where the defect field is light, and more than 60 e-folds of accelerated expansion occur after the symmetry breaking transition. Considered in such a regime, the model is an example of hill-top mechanism, for which analytical expressions giving f_NL can be derived. Parameters leading to significant non-Gaussianity and satisfying observational bounds will be identified. I will also present a SUSY derived hybrid potential and discuss its phenomenology focusing now on a regime where the defect field is heavy and the symmetry breaking transition is fast. Analytical expressions for cosmological observables and curvature perturbations generated by the model will be derived, followed by a numerical analysis.