Circular Polarization of Primordial Gravitational Waves in String-inspired Inflationary Cosmology
Abstract
We study a mechanism to produce the circular polarization of primordial gravitational waves. The circular polarization is generated during the super-inflation driven by the Gauss-Bonnet term in the string-inspired cosmology. The instability in the tensor mode caused by the Gauss-Bonnet term and the parity violation due to the gravitational Chern-Simons term are the essential ingredients of the mechanism. We also discuss detectability of the produced circular polarization of gravitational waves. It turns out that the simple model of single-field inflation contradicts CMB observations. To circumvent this difficulty, we propose a two-field inflation model. In this two-field model, the circular polarization of gravitational waves is created in the frequency range designed by the Big-Bang Observer (BBO) or the deci-hertz gravitational-wave observatory (DECIGO).
Keywords
Cite
@article{arxiv.0706.3585,
title = {Circular Polarization of Primordial Gravitational Waves in String-inspired Inflationary Cosmology},
author = {Masaki Satoh and Sugumi Kanno and Jiro Soda},
journal= {arXiv preprint arXiv:0706.3585},
year = {2008}
}
Comments
11 pages, 7 figures, added new discussions, published version(v3), added references(v4)