Blue Tensor Spectrum from Particle Production during Inflation
Abstract
We discuss a mechanism of particle production during inflation that can result in a blue gravitational wave (GW) spectrum, compatible with the BICEP2 result and with the r < 0.11 limit on the tensor-to-scalar ratio at the Planck pivot scale. The mechanism is based on the production of vector quanta from a rolling pseudo-scalar field. Both the vector and the pseudo-scalar are only gravitationally coupled to the inflaton, to keep the production of inflaton quanta at an unobservable level (the overproduction of non-gaussian scalar perturbations is a generic difficulty for mechanisms that aim to generate a visible GW signal from particle production during inflation). This mechanism can produce a detectable amount of GWs for any inflationary energy scale. The produced GWs are chiral and non-gaussian; both these aspects can be tested with large-scale polarization data (starting from Planck). We study how to reconstruct the pseudo-scalar potential from the GW spectrum.
Keywords
Cite
@article{arxiv.1405.0346,
title = {Blue Tensor Spectrum from Particle Production during Inflation},
author = {Shinji Mukohyama and Ryo Namba and Marco Peloso and Gary Shiu},
journal= {arXiv preprint arXiv:1405.0346},
year = {2015}
}
Comments
18 pages, single-columned, 6 figures