报告摘要：

　　Since the mid‑20th century, condensed‑matter physics has placed great emphasis on developing computational methods: from electronic‑structure theory to molecular dynamics, many techniques for accurately simulating condensed systems have been established and now underpin our understanding of real materials. In recent years our group (mainly graduate students, notably Dr. Qi‑Jun Ye) has increasingly focused on Lee–Yang theory and recognized its practical value for modeling dynamical and thermodynamic behavior in realistic condensed-matter systems. Topics covered include: characterization of phases requiring dynamical information via dynamical partition functions grounded in Lee–Yang theory [1-2]; analysis of Lee–Yang zeroes in the complex phase diagram to quantify the response of thermodynamic properties in the supercritical region [3]; and the use of Lee–Yang zero analysis in quantum many‑body electronic‑structure calculations to help understand and mitigate the fermion sign problem [4]. In this talk, I will begin with the basic ideas of Lee–Yang phase transition theory [5], then present the theoretical framework, numerical implementation strategies, and several recent advances [1-6]. We hope this presentation will prompt renewed interest in Lee–Yang theory as a valuable tool for theoretical studies of complex materials and inspire further work combining it with computational techniques.

References:

【1】Q. J. Ye, L. Zhuang, and X.-Z. Li, Phys. Rev. Lett. 126, 185501 (2021)

【2】Q.-J. Ye and X.-Z. Li, SCPMA 66, 227212 (2023).

【3】X. Y. Ouyang, Q. J. Ye, and X. Z. Li, Phys. Rev. E 109, 024118 (2024)

【4】R. C. He, J. X. Zeng, S. Yang, C. Wang, Q. J. Ye, and X. Z. Li, arXiv:2507.22779v2

【5】叶麒俊、欧阳霄宇、李新征，物理 52, 786 (2023)

【6】L. Liu, Y. H. Dong, Q. J. Ye, and X. Z. Li, Phys. Rev. B 112, 104102 (2025)

报告人简介：

　　Xinzheng Li was born in 1978. He is a Boya Distinguished Professor at Peking University. His research focuses on the development and application of computational methods in condensed matter physics, particularly those related to path integrals and the Lee-Yang phase transition theory. In 2016, his research achievements were selected as one of China's Top 10 Scientific Advances (3/3), and in 2019, he received the First Prize of Natural Science from the Ministry of Education (3/5). In teaching, he has authored one textbook and one academic monograph, and has served as the primary instructor for courses such as Group Theory I, Physics Today, and Advanced Quantum Mechanics (English Version). He has also contributed to the construction of courses like Theory and Computations of Quantum Many-Body Systems and Introduction to Condensed Matter Physics. In 2025, he was awarded the highest teaching accolade in Peking University.