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 $\ell$
(Planck, BICEP2/Keck Array) and high $\ell$ (POLARBEAR, SPTpol, ACTPol).
Benefited from the high precision of CMB data, we obtain the isotropic rotation
angle $\bar{\alpha} = -0.01^\circ \pm 0.37^\circ $ at 68% C.L., the variance of
the anisotropic rotation angles $C^{\alpha}(0)<0.0032\,\mathrm{rad}^2$, the
scale invariant power spectrum $D^{\alpha\alpha}_{\ell \in [2, 350]}<4.71\times
10^{-5} \,\mathrm{rad}^2$ and $r<0.057$ at 95% C.L.. Our result shows that with
the polarization rotation effect, the 95% upper limit on $r$ gets tightened by
17%.
