Non-Gaussianity from Preheating
  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} ~ 50. Our results may provide a useful test of preheating in future CMB experiments. 
Kari Enqvist, Asko Jokinen, Anupam Mazumdar, Tuomas Multamaki and   Antti Vaihkonen