报告题目：Manifestly Gauge-Invariant Cosmological Perturbation Theory from Full Loop Quantum Gravity

报告人：韩慕辛（佛罗里达大西洋大学）

报告时间：2020 年 5 月 7 日 8:30（北京时间）     

报告地点：在线报告（ 腾讯会议 ID：214 657 458 ）

报告摘要：

We apply the full theory of Loop Quantum Gravity (LQG) to cosmology and present a top-down derivation of gauge-invariant cosmological perturbation theory from quantum gravity. The derivation employs the reduced phase space formulation of LQG and the new discrete path integral formulation. We demonstrate that in the semiclassical approximation and continuum limit, the result coincides with the existing formulation of gauge-invariant cosmological perturbation theory. Time evolution of cosmological perturbations is computed numerically from the new cosmological perturbation theory of LQG, and various power spectrums are studied for scalar mode and tensor mode perturbations. Comparing these power spectrums with predictions from the classical theory demonstrate corrections in the ultra-long wavelength regime. These corrections are results from the lattice discretization in LQG. In addition, tensor mode perturbations at late time demonstrate the emergence of spin-2 gravitons as low energy excitations from LQG. The graviton has a modified dispersion relation and reduces to the standard graviton in the long wavelength limit.

报告人简介：  韩慕辛，2005年本科毕业于北京师范大学，2010年博士毕业于柏林洪堡大学与马克斯普朗克引力物理研究所，之后于马赛理论物理中心和埃朗根-纽伦堡大学进行博士后研究，2015年起任教于佛罗里达大西洋大学。