We investigate a possibility of constraining statistical anisotropies of the primordial tensor perturbations by using future observations for the Cosmic Microwave Background (CMB) B-mode polarization. By parameterizing a statistically-anisotropic tensor power spectrum as Ph(k)=Ph(k)∑ngncosnθk, where θk is an angle of the direction of k^=k/k from a preferred direction, we find that it would be possible for future B-mode observations such as CMB-S4 to detect the tensor statistical anisotropy at the level of gn∼O(0.1).
@article{arxiv.1808.08044,
title = {Hunting for Statistical Anisotropy in Tensor Modes with B-mode Observations},
author = {Takashi Hiramatsu and Shuichiro Yokoyama and Tomohiro Fujita and Ippei Obata},
journal= {arXiv preprint arXiv:1808.08044},
year = {2018}
}