学术报告（11月20日 周二 14:30-18:00）

 主持人：姚道新 教授

本报告分上下两部分，每部分1小时30分钟左右，中间休息15分钟。从基本方法讲到最新前沿。

欢迎广大师生前来参与！

【摘要】

Quantum magnets (spin systems) in two dimensions exhibit many unusual phenomena that are currently under intense experimental and theoretical investigation, such as spin liquids and quantum phase transitions that do not fit within the standard Landau-Ginzburg-Wilson paradigm of order parameters. I will discuss a class of theoretical spin models (J-Q models that offer unprecedented access to some of these phenomena through unbiased quantum Monte Carlo (QMC) simulations. In the first part of the lecture, I will discuss the principles of the QMC simulation techniques, and also present methods for analytically continuing QMC-computed imaginary-time correlation functions to real-frequency spectral functions of experimental interest. In the second part, I will show examples of ground states and quantum phase transitions that have recently be studied with these approaches; deconfined quantum critically, phase transitions with enhanced symmetry, and disorder-induced quantum spin liquids. I will illustrate how the numerical results can connect with both quantum field theories and experiments.

【报告人简介】

Anders Sandvik，美国波士顿大学教授，中科院物理所特聘教授，中山大学客座教授，美国物理学会会士（APS Fellow，不超过0.5%），主要研究领域为计算物理和量子相变。 Sandvik教授于芬兰Abo Akademi University获得学士学位（1989），美国University of California圣塔芭芭拉获得博士学位（1993），之后于Florida State University，University of Illinois at Urbana-Champaign，洛斯阿拉莫斯国家实验室，芬兰科学院从事科研工作。2004年至今在美国波士顿大学从事教学科研工作。他所发明的数个量子蒙特卡洛方法在国际上有重要影响，已被广泛使用。Sandvik教授迄今已发表各类论文一百多篇，其中Science 1篇，Physical Review Letters四十多篇，他在2002年关于SSE的文章得 Physical Review E当年最高引用率。