Nagoya University
Theoretical Elementary Particle Physics Laboratory

Date&Time Mon Apr 19 2021 (13:30 - 14:30)
Wen Yin
Affiliation Tohoku Univ.
Title Kilobyte cosmic birefringence and ALP domain walls without strings
Abstract ALP domain walls without strings may be formed in the early Universe. I discuss the mechanisms of the domain wall formation and show the implication on the birefringence of cosmic microwave background (CMB) polarization. For domain walls following the scaling solution, both isotropic and anisotropic cosmic birefringence are predicted. The prediction is insensitive to the model parameter choice. Surprisingly, the magnitude of the isotropic birefringence can explain the recently reported value, while the anisotropic one is also consistent with the observation. The detection of both signals will be a smoking-gun evidence for the scenario.