报告题目（Title）：Group cohomology and algebraic topology as the mathematical theory for Symmetry protected topological order in physics

报告人（Speaker）：Xiao-Gang Wen（Dept. of Physics, MIT）

时间(Time)：2014年12月24日(星期三)下午14：00-17:00

14:00--15:20 Lecture One

15:20--15:40 Tea Time

15:40--17:00 Lecture Two

地点(Place)：郑裕彤讲堂

摘要（Abstract）：

Symmetry protected topological (SPT) states are a new kind of quantum states of matter, which are beyond Landau symmetry breaking theory and cannot be described by group theory. As new state of matter, SPT states have many new properties, such as non-trivial gapless boundary and point defects with fractional statistics. In these two lectures, I will present

(1) a systematic theory of SPT order based on non-linear sigma model and its topological terms, which turns out to be a group cohomology theory

(2) ways to probe/measure SPT orders, and the connection to gauge/gravitational anomalies, which turns out to be an algebraic topology theory

(3) mechanism to generate SPT orders