主讲人：唐紫瑜 韩国基础科学研究院

时间：2025年12月19日13：30

地点：徐汇校区十号楼222室

举办单位：数理学院

主讲人介绍：Zi-Yu Tang, Ph.D. in Science, graduated from the School of Physics and Astronomy, Shanghai Jiao Tong University (Theoretical Physics). She is currently a Postdoctoral Fellow at the Institute for Basic Science (IBS), South Korea, and previously pursued postdoctoral research at UCAS Hangzhou Advanced Research Institute. Her research focuses on gravitational theory and black hole physics, including black hole solutions, thermodynamics, shadows, and superradiance. She has led projects like the National Natural Science Foundation of China and China Postdoctoral Science Foundation, published in top international journals, delivered talks at international conferences, and received multiple scholarships. With teaching assistant experience, she has made notable achievements in theoretical physics.

内容介绍：It is known that the axion-photon coupling can lead to quantum stimulated emission of photons and classic exponential amplification of electromagnetic (EM) fields at half the axion mass frequency, when the axion density or the coupling constant is sufficiently large. In this work, we studied the EM photon cloud induced from an axion cloud around a Kerr black hole in the first order of the coupling constant classically. In the presence of a static EM background (like Wald extended solution valid in realistic astrophysical environment), we found that an EM photon cloud emerges, oscillating at the same frequency as the axion cloud and growing exponentially in accordance with the axion cloud when the superradiant condition for the axion field is satisfied. The evolution of the EM photon cloud with time and azimuthal angle is obtained analytically while the cross-sectional distribution is solved numerically. The induced EM field exhibits significantly different symmetries in contrast to the background EM field, which may serve as an indication of the existence of both an axion cloud and axion-photon coupling.