(Seminar) Lefschetz Thimble Path Integral and its Application to Spin-Foam Model

CAS Key Laboratory of Theoretical Physics

Institute of Theoretical Physics

Chinese Academy of Sciences

Seminar

Title

题目

Lefschetz Thimble Path Integral and its Application to Spin-Foam Model

Speaker

报告人

黄子鬯                

Affiliation

所在单位

Fudan University

Date

日期

2:00pm, Jan 13, 2021, Wednesday

Venue

地点

https://zoom.com.cn/j/95080629513

Contact Person

所内联系人

Gang Yang

Abstract

摘要

The numerical sign problem is known as the problem of evaluating the high oscillatory functions by numerical method. In many physics problems involving complex valued actions, the sign problem prevents people from using the conventional Monte Carlo method to numerically evaluate the expectation values of the observables. Many recent progresses suggest to apply the Picard-Lefschetz theory to cure the sign problem. In my work, an algorithm combining the Lefschetz thimble method and Differential Evolution Adaptive Metropolis (DREAM) algorithm is proposed to compute the expectation values of any observables in any system suffering from the sign problem. In particular, this algorithm is applied to compute the spin foam propagator, which is a 2-point correlation function introduce in the Loop Quantum Gravity (LQG) theory.