活动名称：From the reduced Lagrangian to QNM problems

时间：2026年9月20日（星期日）时间点11:20

地点：博雅楼 503

主讲人：张超

主办单位：重庆师范大学物理与光电工程学院

主讲人简介：张超，本科毕业于北京航空航天大学物理学院、博士毕业于美国Baylor University，后赴浙江工业大学理学院与日本东京理科大学理学部从事博士后研究，现于中国石油大学（北京）理学院担任副教授。主要研究兴趣在于引力波、引力理论、黑洞物理等，先后在PRD、JCAP、EPJC、CPC等国内外相关领域主流期刊上发表论文十余篇，并主持了一项国自然青年基金项目（已结题）、校级拔尖人才项目、参与了一项国自然面上项目。近期研究聚焦了洛伦兹破缺引力理论、极端质量比天体系统、引力的实验检验、圈量子黑洞等问题。

活动简介：Gravitational-perturbation problems are essential in gravitational-wave (GW) investigations. Perturbing the background spacetime generally leads to coupled partial differential equations of gauge invariants, which can sometimes pose formidable technical challenges for further analyses, such as quasi-normal mode (QNM) calculations. Overcoming these difficulties through a reduced Lagrangian approach, we integrate out non-dynamical degrees of freedom, yielding a compact quadratic action governing the evolution of gauge invariants. In addition to facilitating QNM analyses of the ringdown signal of black holes, the results reveal novel stability constraints for various modified theories of gravity. Furthermore, together with observational constraints from GWs, we shall build up a more comprehensive as well as systematic understanding of the theory, serving for joint tests of gravity.