Non-Gaussianity from instant and tachyonic preheating

Enqvist, Kari and Jokinen, Asko and Mazumdar, Anupam and Multamaki, Tuomas and Vaihkonen, Antti (2005) Non-Gaussianity from instant and tachyonic preheating. Journal of Cosmology and Astroparticle Physics, 2005 (3). ISSN 1475-7516

Abstract

We study non-Gaussianity in two distinct models of preheating: instant and tachyonic. In instant preheating non-Gaussianity is sourced by the local terms generated through the coupled perturbations of the two scalar fields. We find that the non-Gaussianity parameter is given by $f_{NL}^{\phi}\sim 2g