@article{0f5fbe6242d6466698123bae42bc05a1,
title = "Statistically anisotropic tensor modes from inflation",
abstract = "We consider the inflationary universe with a spectator scalar field coupled to a U(1) gauge field and calculate curvature perturbation and gravitational waves (GWs). We find that the sourced GWs can be larger than the one from vacuum fluctuation and they are statistically anisotropic as well as linearly polarized. The GW power spectrum acquires higher multipole moments with respect to the angle θ between a wave number k and a background vector field as h∝ (1-cos2θ+cos4θ-cos6θ) irrespective of the model parameters.",
keywords = "Inflation, physics of the early universe",
author = "Tomohiro Fujita and Ippei Obata and Takahiro Tanaka and Shuichiro Yokoyama",
note = "Funding Information: This work was supported in part by MEXT KAKENHI Grant Numbers 17J09103 (T.F.), 15J01345 (I.O.), 17H06357 and 17H06358 (T.T.), and 15K17659 (S.Y.) as well as the Grant-in-Aid for Scientific Research No. 26287044 and 15H02087 (T.T.), and 16H01103 (S.Y.). Publisher Copyright: {\textcopyright} 2018 IOP Publishing Ltd and Sissa Medialab.",
year = "2018",
month = jul,
day = "12",
doi = "10.1088/1475-7516/2018/07/023",
language = "English",
volume = "2018",
journal = "Journal of Cosmology and Astroparticle Physics",
issn = "1475-7516",
publisher = "IOP Publishing Ltd.",
number = "7",
}