Non-Gaussianity from preheating

Phys Rev Lett. 2005 Apr 29;94(16):161301. doi: 10.1103/PhysRevLett.94.161301. Epub 2005 Apr 29.

Abstract

We consider a two-field model for inflation where the second order metric perturbations can be amplified by a parametric resonance during preheating. We demonstrate that there can arise a considerable enhancement of non-Gaussianity sourced by the local terms generated through the coupled perturbations. We argue that the non-Gaussianity parameter could be as large as f(NL) approximately 50. Our results may provide a useful test of preheating in future cosmic microwave background experiments.