Mixed perturbations from an inflaton and two curvatons: Towards understanding non-Gaussianity in more complicated curvaton scenarios

作者：Sueiro Maria^*; Fairbairn Malcolm

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2013, 87(4): 043524.

DOI：10.1103/PhysRevD.87.043524

We analyze the situation in which the primordial curvature perturbations are produced by the joint effects of an inflaton field and two curvaton fields. We present general equations which allow the reader to obtain f(NL) for several different scenarios, which differ in the order in which fields decay into radiation after inflation. In order to investigate the physics of these equations, we analyze some simplified situations where the fields are harmonic and both curvatons are frozen at the same expectation value during inflation. We find quite complex behavior-for a given situation where the inflaton contributes a fixed amount to the total curvature perturbation, there are situations where f(NL) is maximized if both curvatons share equally in contributing the rest, and situations where f(NL) is maximized if only one of the two curvatons contributes the rest. We are unable, therefore, to make any completely general extrapolations about the expected non-Gaussianity from N curvatons. We find that as the curvaton contribution to the overall perturbation is gradually increased, f(NL) rises to a maximum before falling again, and that a given f(NL) can correspond to many different parameter sets for the two curvatons. DOI: 10.1103/PhysRevD.87.043524

• 出版日期2013-2-19