Joint constraint on primordial gravitational waves and polarization rotation angle with current CMB polarization data.

Cosmological CPT violation will rotate the polarized direction of CMB photons, convert partial CMB E mode into B mode and vice versa. It will generate non-zero EB, TB spectra and change the EE, BB, TE spectra. This phenomenon gives us a way to detect the CPT-violation signature from CMB observations, and also provides a new mechanism to produce B mode polarization. In this paper, we perform a global analysis on tensor-to-scalar ratio r and polarization rotation angles based on current CMB datasets with both low ℓ (Planck, BICEP2/Keck Array) and high ℓ (POLARBEAR, SPTpol, ACTPol). Benefited from the high precision of CMB data, we obtain the isotropic rotation angle α ¯ = 0.0 ∘ ± 0.37 ∘ at 68% CL, the variance of the anisotropic rotation angles C α (0) < 0.0032 rad 2 , the scale invariant power spectrum D ℓ ∈ [ 2 , 350 ] α α < 4.65 × 10 − 5 rad 2 and r < 0.059 at 95% CL. Our result shows that with the polarization rotation effect, the 95% upper limit on r gets tightened by 14%. [ABSTRACT FROM AUTHOR]