Recently, the cross-correlation between E- and B-mode polarization of the cosmic microwave background, which is well explained by cosmic birefringence with rotation angle β≈0.3 deg, has been found in cosmic microwave background polarization data. We carefully investigate the possibility of explaining the observed EB correlation by the primordial chiral gravitational waves, which can be generated in the parity-violating theories in the primordial Universe. We found that the chiral gravitational wave scenario does not work due to the overproduction of the BB autocorrelation, which far exceeds the observed one by SPTPol and POLARBEAR.
ASJC Scopus subject areas
- Nuclear and High Energy Physics