报告题目：Twisted Quantum Double Model of Topological Orders with Boundaries

报告人：万义顿 教授（ 复旦大学）

报告时间：2020年 1 月 7 日（ 周二） 9： 30 ~ 10： 30

报告地点：北洋园校区理学院32教256

报告摘要：

We generalize the twisted quantum double model of topological orders in two dimensions to the case with boundaries by systematically constructing the boundary Hamiltonians. Given the bulk Hamiltonian defined by a gauge group G and a 3-cocycle in the third cohomology group of G over U (1), a boundary Hamiltonian can be defined by a subgroup K of G and a 2-cochain in the second cochain group of K over U (1). The consistency between the bulk and boundary Hamiltonians is dictated by what we call the Frobenius condition that constrains the 2-cochain given the 3-cocyle. We offer a closed-form formula computing the ground-state degeneracy of the model on a cylinder in terms of the input data only, which can be naturally generalized to surfaces with more boundaries. We also explicitly write down the ground-state wave function of the model on a disk also in terms of the input data only.

报告人简介：万义顿：男，复旦大学物理系教授，华南理工大学计算机与经济学双学士（1998）、美国宾夕法尼亚大学计算机硕士（2002）、加拿大渥太华大学物理硕士（2004）、加拿大滑铁卢大学暨圆周理论物理研究所理论物理博士（2009），于日本近畿大学、东京大学、加拿大圆周理论物理研究所做博士后，2016年加入复旦物理系，从事拓扑物态、量子信息与计算、量子引力等领域的交叉研究。