Flat-band Ferromagnetism of the SU(N) Hubbard Model on Tasaki Lattices

报告摘要：We present exact solutions of repulsive SU(N) Hubbard models in lattices with flat band. We prove the SU(N) Hubbard model can be mapped to a classical percolation problem for all lattices with flat-band in arbitrary dimensions, provided the quasi-locality and local-connectivity conditions are satisfied. We then consider 1D and 2D Tasaki lattices as examples and solve for the para-ferro magnetic phase transition points. We also rigorously prove the existence of ferromagnetic state for arbitrary values of N and dimensionalities if the single-particle flat-band is 1/N filled. Our work provides a starting point and benchmark for future analysis on SU(N) systems.
报告人简介：张威，2006年美国佐治亚理工学院物理系博士毕业，之后在密歇根大学做博后。08年起加入中国人民大学，现在是物理系教授, 中国人民大学教务处副处长。主要从事原子分子物理和量子信息领域的理论研究，在国际期刊发表学术论文60 余篇，出版英文教材和专著 3 部，翻译出版多部科普作品。先后入选教育部新世纪优秀人才、北京市科技新星、国家自然科学基金委优秀青年科学基金、教育部长江学者奖励计划青年学者等人才计划。