2011/07/20 by Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada +5
Computer Science · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Axion #COSMIC cancer database #Computational Physics and Python Applications #Constant (computer programming) #Cosmology #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark energy #Dark matter #Dark radiation #Exponential decay #Geography #Hubble's law #Magnetic monopole #Mass fraction #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum mechanics #astro-ph.CO #hep-ph
paper · pdf · doi:10.1103/physrevlett.127.181103
6 pages, 2 figures
openalex publication_date 2011/07/20 · openalex created_date 2016/06/24 · arxiv created 2021/03/15 · arxiv updated 2021/11/10 · openalex updated_date 2026/08/06
Cosmic birefringence is predicted if an axionlike particle (ALP) moves after the recombination. We show that this naturally happens if the ALP is coupled to the dark matter density because it then acquires a large effective mass after the matter-radiation equality. Our scenario applies to a broad range of the ALP mass mϕ≲10-28 eV, even smaller than the present Hubble constant. We give a simple model to realize this scenario, where dark matter is made of hidden monopoles, which give the ALP such a large effective mass through the Witten effect. The mechanism works if the ALP decay constant is of order of the grand unified theory scale without a fine-tuning of the initial misalignment angle. For smaller decay constant, the hidden monopole can be a fraction of dark matter. We also study the implications for the QCD axion, and show that the domain wall problem can be solved by the effective mass.