报告题目：

Exotic quantum phases with ultracold bosonic gases in optical lattices

报告人：

李永强 （国防科技大学，副教授）

报告时间：

2017年12月22日（星期五），下午2:00

报告地点：

大学城理六栋302会议室

报告摘要:

In this talk, I would like to introduce quantum phenomena in strongly correlated ultracold bosons in optical lattices. First, I will talk about supersolidity of two-component bosonic atoms on a square lattice, where one species is weakly dressed to an electronically Rydberg state, generating a tunable, soft-core shape long-range interaction. Using a dynamical mean-field calculation, we find that interspecies onsite interactions can stabilize a pronounced region of supersolid phases. This is characterized by two distinctive types of supersolids, where the bare species forms supersolid phases that are immersed in strongly correlated quantum phases. We show that the interspecies interaction leads to a roton instability in the bare species and therefore is crucially important to the supersolid formation. Second, I will take about heteronuclear magnetism in the Mott-insulating regime. Different from the identical mixtures where the boson (fermion) statistics only admits even (odd) parity states from angular momentum composition, for heteronuclear atoms in principle all angular momentum states are allowed, which can give rise to new magnetic phases. Various magnetic phases can be developed over these degenerate spaces. We unveil these rich phases using the bosonic dynamical mean-field theory approach.

参考文献:

[1] Y.-Q. Li, W-B. Li, A. Geissler and W. Hofstetter, Onsite interaction enhanced supersolidity of strongly correlated bosons in optical lattices, arXiv:1705.01026.

[2] Y.-Q. Li, M. Gong and J.-M. Yuan, Hetero magnetism with ultracold spinor gases in optical lattices, arXiv:1711.01203.

报告人简介:

Dr. Yongqiang Li is currently an associate professor in National University of Defense Technology. He obtained his PhD from Frankfurt University in Germany in 20012 and bachelor degree from National University of Defense Technology in 2005. His research interests include ultracold atomic gases in optical lattices with strong correlations, many-body effects, and exotic quantum phenomena.