报告题目：相互作用玻色系统中的杨单极和连续多重简并(Yang monopoles and emergent continuous degenerate manifolds in interacting bosons)
报 告 人：严杨千 博士 (普度大学物理天文系 博士后)
报告时间：2017年9月30日（周六）10:00
报告地点：校本部G309
邀请人：张永平
报告摘要：
Yang monopole as a zero-dimensional topological defect has been well established in multiple fields in physics. However, it remains an intriguing question to understand interaction effects on Yang monopoles. Here, we show that collective motions of many interacting bosons give rise to exotic topological defects that are distinct from Yang monopoles seen by a single particle. Whereas interactions may distribute Yang monopoles in the parameter space or glue them to a single giant one of multiple charges, three-dimensional topological defects also arise from continuous manifolds of degenerate many-body eigenstates. These defects are characterized by Z2 invariants, and their projections in lower dimensions lead to knotted nodal lines and nodal rings, which carry finite linking numbers. Our results suggest that ultracold bosonic atoms can be used to create emergent topological defects and directly measure topological invariant that are not easy to access in solids.
