paper

Curvaton with Nonminimal Derivative Coupling to Gravity II: Full Perturbation Analysis

arXiv:1409.2949 · doi:10.1103/PhysRevD.90.123508

Abstract

In our previous work \cite{Feng:2013pba}, we have shown a curvaton model where the curvaton has a nonminimal derivative coupling to gravity. Such a coupling could bring us scale-invariance of the perturbations for wide range constant values of the equation-of-state of the cosmic background at the early time. In this paper, we continue our study by fully analyzing its perturbations up to the third order. Apart from the usual 2-point correlation function that has already been calculated in \cite{Feng:2013pba}, we have also taken into account the 3-point correlation functions including pure scalar part, pure tensor part, as well as the cross-correlations between scalar and tensor perturbation modes. We find that for pure scalar part, the 3-point correlation functions can generate non-Gaussianities that fits the PLANCK data very well. For pure tensor and mixed parts, the shape functions have peaks at squeezed and equilateral limits respectively, responsible for sizable and , which could be tested by the future observatioanl data.

Published in Phys.Rev. D90 (2014) 123508

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Curvaton with Nonminimal Derivative Coupling to Gravity II: Full Perturbation Analysis · wovepaper