Title：Monte Carlo simulation on a Lefschetz thimble:application to Lorentzian spin foam amplitudes

Speaker：Dongxue Qu

Department of Physics, Florida Atlantic University

Time：August 5, 2019 (Thursday) 15:30 PM

Venue：333 Lecture Hall, Physics Building, South Qianwei Campus

Abstract：

The Lorentzian spin foam amplitude for loop quantum gravity is a multi-dimensionalintegral of highly oscillating functions. It‘s impossible to use Monte Carlo method directlybecause of sign problem. Using a method based on deforming the integral region on aLefschetz thimble, we are able to numerically calculate the vertex amplitude. We firstintroduce Monte Carlo algorithm to sample the domain thimble in loop quantum gravity. Byusing this method to calculate amplitude, the efficiency can be greatly improved.

Brief Bio:

DongxueQu obtained her B.S. and M.S.atBeijing Jiaotong University in 2014 and 2017. Now she is studying in Florida Atlantic University (Prof. Muxin Han’s group, America) as a Ph.D.student. Her research interest is loop quantum gravity. Now her research is mainly to numericallysimulate spin foam amplitude in Euclidean and Lorentzian space.