An inflationary model with small scalar and large tensor nongaussianities
Abstract
We study a model of inflation where the scalar perturbations are almost gaussian while there is sizable (equilateral) nongaussianity in the tensor sector. In this model, a rolling pseudoscalar gravitationally coupled to the inflaton amplifies the vacuum fluctuations of a vector field. The vector sources both scalar and tensor metric perturbations. Both kinds of perturbations are nongaussian, but, due to helicity conservation, the tensors have a larger amplitude, so that nongaussianity in the scalar perturbations is negligible. Moreover, the tensors produced this way are chiral. We study, in the flat sky approximation, how constraints on tensor nongaussianities affect the detectability of parity violation in the Cosmic Microwave Background. We expect the model to feature interesting patterns on nongaussianities in the polarization spectra of the CMB.
Cite
@article{arxiv.1307.7077,
title = {An inflationary model with small scalar and large tensor nongaussianities},
author = {Jessica L. Cook and Lorenzo Sorbo},
journal= {arXiv preprint arXiv:1307.7077},
year = {2013}
}
Comments
13 pages, 4 figures. A minor change in the title, a few points clarified, one note and one reference added, agrees with published version