We take a more detailed look at the recently proposed magnetogenesis mechanism triggered by ultralight dark matter coupled to electromagnetism. The proposed mechanism made use of a tachyonic resonance channel which leads to the exponential amplification of infrared modes. Here, we first investigate a possible narrow band parametric resonance channel which can produce photons at higher frequencies. Secondly, we estimate the effects of back-reaction on terminating the resonance. We find that there is indeed a narrow resonance channel. It is characterized by a Floquet exponent which is slightly smaller than the corresponding exponent for the tachyonic resonance. However, there is a region of parameter space (corresponding to a very small coupling constant) for which the tachyonic resonance is ineffective. In this case, the narrow resonance will dominate, and it will still be sufficiently strong to generate the observed magnetic fields on cosmological scales. Our analytical treatment of the back-reaction effects considered here indicates that a fraction of order one of the initial dark matter density can flow into the gauge fields. Hence, our magnetogenesis scenario appears to be robust to back-reaction effects.
Ultralight Boson Ionization from Comparable-Mass Binaries
Shanghai Jiao Tong University（上海交通大学）；CENTRA, Departamento de Física, Instituto Superior Técnico – IST, Universidade de Lisboa – UL（里斯本大学高级技术学院物理系CENTRA中心）；Tsung-Dao Lee Institute, Shanghai Jiao Tong University（上海交通大学李政道研究所）；Dipartimento di Fisica, Sapienza Università di Roma & INFN, Sezione di Roma（罗马第一大学物理系及罗马INFN分部）；Walter Burke Institute for Theoretical Physics, California Institute of Technology（加州理工学院沃尔特·伯克理论物理研究所）
Seeing in the Dark: Gravitational Waves from Resonant Production of Dark Photon Dark Matter
University of California, Riverside（加州大学河滨分校）；Asia Pacific Center for Theoretical Physics (APCTP)（亚太理论物理中心）；Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK)（高能加速器研究机构粒子与核研究研究所）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Harvard University（哈佛大学）
