报告题目:Exceptional lines of Reissner-Nordström-de Sitter black hole surrounded by a thin shell of matter

报告人：吴良碧

报告时间：2026年8月18日（周二）下午 14:30 – 16:00

报告地点：浙江工业大学理学楼二楼师生活动中心

摘要（Abstract）：We study exceptional lines (ELs) in the quasinormal modes (QNMs) of Reissner-Nordström-de Sitter black hole surrounded by a static thin shell of matter. For a conformally scalar perturbation, we derive the QNM condition by matching the interior and exterior solutions across the shell and show that higher overtones are particularly sensitive to variations of the shell and background parameters. A mode permutation between two QNMs reveals an exceptional point (EP). After extending the parameter space, this degeneracy forms a continuous EL. We show that the spectral response near the line is intrinsically directional. For a perturbation in parameter space εû, the QNM splitting is |ω₊ − ω₋| = Cû√ε + o(√ε), with Cû = (ûᵀKû)¹/⁴ and K is so-called spectral sensitivity anisotropy matrix. The tangent direction of EL is a null direction of K, so that the leading square-root splitting vanishes along the exceptional line, whereas the two principal directions in the normal plane exhibit different sensitivities. Furthermore, the square-root branch structure makes conventional linear QNM parametrizations singular near an EL. We therefore construct an EL adapted parametrization which incorporates both the local geometry of the line and the nonanalytic QNM splitting.

报告人简介（Bio）：吴良碧现为国科大杭州高等研究院博士后。2023年博士毕业于中国科学技术大学理论物理专业。随后任国科大杭州高等研究院博士后，从事黑洞物理与引力波理论研究。具体兴趣包括黑洞似正规模的（不）稳定性、非厄米物理在黑洞中的应用以及引力波数据分析等等。迄今已在PRD、SCPMA、EPJC等期刊发表学术论文18篇。获得国自然青年基金项目C类资助。

邀请人：朱涛 教授