报告题目：Testing ultralight scalar field dark matter in high-redshift universe

报告人：李博华助理教授（广西大学）

主持人：訾铁光 博士

报告时间：2024年4月24日（星期三）下午3:00

报告地点：物理楼（18号楼）二楼220室  

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                                     物理与光电学院

                                     2024年4月22日

报告摘要：

Scalar field dark matter (SFDM) comprised of ultralight (m10^{−22} eV) bosonic particles has received significant attention as a viable alternative to Cold Dark Matter (CDM), as it approximates CDM on large scales (~1 Mpc) while potentially resolving some of its small-scale problems via kpc-scale quantum interference. However, the basic SFDM model described by a free real field, a.k.a. fuzzy dark matter (FDM), is recently challenged by a catch-22 problem: small boson masses yield the desired cores of dwarf galaxies but underpredict structure in the Lyman-αforest, whereas large boson masses render FDM effectively identical to CDM. Therefore, we propose to study the complex SFDM model with a possible self-interaction. A complex scalar field with U(1) symmetry results in the associated Noether current, a new degree of freedom. We examine the dynamical implications of the Noether charge for large-scale structure and the Cosmic Microwave Background. We also discuss potential tests of SFDM by the 21cm line from the Cosmic Dawn and by the gravitational-wave (GW) signal from spinning black holes. Furthermore, we demonstrate that the kination phase resulted from complex SFDM can amplify the primordial GW background and thus explain the recent pulsar timing array results.

报告人简介：

李博华2017年博士毕业于美国得克萨斯大学奥斯汀分校，此后在清华大学天文系进行博士后研究，2021年加入广西大学物理学院担任助理教授。李博华的研究领域为暗物质和早期宇宙，特别关注标量场暗物质模型在宇宙大尺度结构和早期宇宙中的检验，以及引力波、CMB、21厘米线等宇宙学探针。目前主持一项国家自然科学基金项目。