主讲人：苗兵 教授（中国科学院大学）

题目：Exact Theory of Calculating Fluctuations

时间：2023年08月25日（周五）上午10:00

地点：理工楼1201

报告摘要：

Equilibrium and non-equilibrium fluctuations are important topics in statistical physics. Quantitatively capturing fluctuation effects usually reduces to the evaluation of functional or fluctuation determinant of the Hessian operator relevant to the problem under study. For example, it gives the one-loop fluctuation energy beyond mean field theory in phase transition theory, the leading factor contribution of stochastic fluctuations beyond large deviation theory. Usually calculating fluctuation determinant resorts to the operator spectrum, such as in the zeta function method. In this talk, I will discuss several exact methods to calculate fluctuation determinant in 1D field theory when the operator spectrum is unsolvable in the case of non-trivial saddle point solution. The methods include contour integral method based on the argument principle in complex analysis, the Pauli-van Vleck-Morette method based on path integral, the Feynman-Kac formula in stochastic dynamics, and the generalized Gelfand-Yaglom theorem in differential operator. The equivalence between these different methods will be established through deriving them systematically.

个人简介：

苗兵，中国科学院大学教授，博士生导师。研究领域为统计物理和软凝聚态理论。2006年博士毕业于中科院化学所理论高分子物理组。2006年5月-2008年9月先后在加拿大圣弗朗西斯泽维尔大学和圭尔夫大学物理系做博士后。 2008年10月-2011年2月在德国马普高分子研究所理论系解析理论组做博士后。2009年7月在法国理论物理夏季学校 ( Les Houches School of Physics ) 研究生物体系中的物理和力学。2019年3月和9月分别任德国马普智能体系研究所和法国波尔多大学理论物理组访问教授。自2020年6月任兰州大学物理学院兼职教授。