%0 Journal Article
%T Cosmic Birefringence Fluctuations and Cosmic Microwave Background $B$-mode Polarization
%A Seokcheon Lee
%A Guo-Chin Liu
%A Kin-Wang Ng
%J Physics
%D 2014
%I arXiv
%X Recently, BICEP2 measurements of the cosmic microwave background (CMB) $B$-mode polarization has indicated the presence of primordial gravitational waves at degree angular scales, inferring the tensor-to-scalar ratio of $r=0.2$ and a running scalar spectral index. In this {\em Letter}, we show that the existence of the fluctuations of cosmological birefringence can give rise to CMB $B$-mode polarization that fits BICEP2 data with $r<0.11$ and no running of the scalar spectral index. Thus, it might be too hasty to conclude that many inflation models with small $r$ are ruled out based on BICEP2 result.
%U http://arxiv.org/abs/1403.5585v4