题 目：Fidelity zeros and Lee-Yang theory of quantum phase transitions
报告人：孙高永 南京航空航天大学
时 间：2026年05月07日（星期四) 下午15：00
地 点：虎溪校区理科楼物理学院 LE201
邀请人：许东辉
报告摘要：Lee-Yang theory is central to the analysis of thermal phase transitions. However, the underlying mechanism of the theory and the nature of Lee-Yang zeros in quantum many-body systems remain elusive. In this talk, I will present a unified framework for understanding quantum phase transitions from fidelity zeros induced by non-Hermitian symmetry breaking. These zeros, arising from transitions between symmetry sectors, obey the Lee-Yang theorem and give rise to fidelity edges near critical points. Quantum criticality is further characterized through the finite-size scaling of fidelity zeros. As concrete examples, we investigate fidelity zeros analytically in one-dimensional and numerically in two-dimensional quantum Ising models under a complex magnetic field, showing excellent agreement with analytical theory and with quantum Monte Carlo and tensor-network simulations.
孙高永，副研究员。2015年于德国汉诺威大学获得博士学位，2015-2017年在德国马克斯普朗克复杂系统物理研究所从事博士后研究，2017年在南京航空航天大学工作。迄今为止，在Phys. Rev. Lett., Phys. Rev. A/B/Research 等期刊上发表学术论文30余篇。