Nongaussian Isocurvature Perturbations from Inflation

Abstract

We present a class of very simple inflationary models of two scalar fields which leads to nongaussian isothermal perturbations with "blue" spectrum, n > 1. One of the models is inspired by supersymmetric theories where light scalar fields naturally acquire masses of the order of the Hubble constant H during inflation. Another model presumes that one of the fields has a nonminimal interaction with gravity. By a slight modification of parameters of these models one can obtain either gaussian isothermal perturbations, or nongaussian adiabatic perturbations with n > 1.

Few misprints are corrected; results are not changed. It is noted that our results for the most natural range of parameters correspond to the spectral index of isothermal perturbations n ~1.6