题  目： Interacting integer topological phases in two dimensions

报告人：  路元明 博士
时  间： 2012年8月20日(星期一)上午10:00
地  点：  中心教学楼701
ABSTRACT
We study topological phases of interacting systems in two spatial dimensions in the absence of topological order (i.e. with a unique ground state on closed manifolds and no fractional excitations). These are the closest interacting analogs of integer quantum Hall states, topological insulators and superconductors. We adapt the well-known Chern-Simons effective theory description of quantum Hall states to classify such `integer' topological phases. Our main result is a general formalism that incorporates symmetries into the effective theory description. Remarkably, this simple analysis yields the same list of topological phases as a recent group cohomology classification, and in addition provides field theories and explicit edge theories for all these phases. The bosonic topological phases, which only appear in the presence of interactions and which remain well defined in the presence of disorder include (i) bosonic insulators with a Hall conductance quantized to even integers (ii) a bosonic analog of quantum spin Hall insulators and (iii) a bosonic analog of a chiral topological superconductor. We also discuss interacting fermion systems, where we find the present formalism automatically takes interaction effect into account. The fermionic topological phases include charge-4e topological superconductors with or without time reversal symmetry. Lastly we construct microscopic models of these phases from coupled one-dimensional systems.
Reference: http://arxiv.org/abs/1205.3156

简  历:
路元明，清华大学基科班本科毕业，美国Boston colleage 拿到博士学位， 现在美国University of California, Berkeley 从事博士后研究。主要研究的领域为强关联电子系统理论，拓扑绝缘体、拓扑超导体等。在PRL,PRB等国际高水平刊物上发表论文多篇。

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