报告题目:Covariant effective dynamics, generalized LTB spacetime and dust collapse in polymerized spherical symmetric models

报告人：刘洪光 博士（德国埃尔朗根-纽伦堡大学）

报告时间：2023年9月22日（周五）下午 13:30-15:30

报告地点：浙江工业大学理学楼A 二楼师生活动中心

摘 要 (Abstract): We propose a method to construct mubar-scheme effective dynamics in the spherical symmetric spacetime (polymerized models) which is generally covariant as derived from a covariant Lagrangian. The Lagrangian belongs to the class of extended mimetic gravity Lagrangians in 4 dimensions. We then derive compatible Lemaitre-Tolman-Bondi (LTB) conditions for polymerized models in this framework. Our results show that there exist a class of effective models for which the dynamics decouples completely along the radial direction in LTB coordinate. This subsector of theories admit a Birkhoff-like theorem. Following the analysis, we provide a systematic procedure to construct effective spherically symmetric models encoding loop quantum gravity modifications as $1+1$ field theory models encoding consistent LTB conditions, covariance and compatibility with the improved dynamics of loop quantum cosmology in the cosmological and LTB sector. As concrete examples of our generalized strategy we obtain and compare with different phenomenological models which have been investigated recently and demonstrate resolution of singularity by quantum geometry effects via a bounce.

报告人简介(Bio): 刘洪光博士，2015年本科毕业于北京师范大学，2020年于法国艾克斯-马赛大学获得博士学位，2020年至今在德国埃尔朗根-纽伦堡大学从事博士后研究。主要研究领域为量子引力，包括正则量子引力和spinfoam模型及其相关的有效黑洞和宇宙学模型，以及修正引力理论，尤其是Beyond Hordenski和DHOST理论。

邀请人：李瀑飞 博士