2019/09/30 by Emi Masaki, Arata Aoki, Jiro Soda
Physics and Astronomy · #Atomic and Subatomic Physics Research #Axion #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Instability #Magnetic field #Particle physics #Photon #Physics #Quantum electrodynamics #Quantum mechanics #Universe #astro-ph.CO #hep-ph #hep-th
paper · pdf · doi:10.1103/physrevd.101.043505
published as Phys. Rev. D 101, 043505 (2020) · 29 pages, 5 figures, published version
openalex publication_date 2020/02/05 · arxiv created 2020/02/11 · arxiv updated 2020/02/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
It is known that a coherently oscillating axion field is a candidate of the dark matter. In the presence of the oscillating axion, the photon can be resonantly produced through the parametric amplification. In the universe, there also exist cosmological magnetic fields which are coherent electromagnetic fields. In the presence of magnetic fields, an axion can be converted into a photon, and vice versa. Thus, it is interesting to investigate what happens for the axion-photon system in the presence of both the axion dark matter and the magnetic fields. This system can be regarded as a coupled system of the axion and the photon whose equations contain the Mathieu type terms. We find that the instability condition is changed in the presence of magnetic fields in contrast to the conventional Mathieu equation. The positions of bifurcation points between stable and unstable are shifted and new instability bands appear. This is because the resonantly amplified axion can be converted to photon, and vice versa.