报告题目： Multi-component quantum hall effects in topological flat bands
报 告 人：曾天生 (The University of Texas at Dallas)
报告时间：2018年9月13 日（周四）10:00
报告地点：校本部E106
报告摘要：
The integer valued symmetric K-matrix classifies the topological order at different fillings for multicomponent Abelian systems, which is the vital of Chern-Simons field theory. In this talk, I’ll report our recent progress on quantum Hall states for multi-component particles (hardcore bosons and fermions) loading in topological lattice models through exact diagonalization (ED) and density-matrix renormalization group (DMRG). Firstly, by tuning the interplay of interspecies and intraspecies interactions, we demonstrate that two-component fractional quantum Hall states emerge at certain fractional filling factors v=1/2 for fermions (v=2/3 for bosons) in the lowest Chern band, classified by features from ground states including the unique Chern number matrix (inverse of K-matrix), the fractional charge and spin pumpings, and two parallel propagating edge modes. Moreover, we also apply our strategy to two-component fermions at integer filling factor v=2, where a possible topological Neel antiferromagnetic phase is under intense debate very recently. By tuning the onsite Hubbard repulsion, we establish a first-order phase transition directly from a two-component fermionic v=2 quantum Hall state at weak interaction to a topologically trivial antiferromagnetic insulator at strong interaction, and therefore exclude the possibility of an intermediate topological phase for our system. At last, I’ll talk about the generalization of multi-component quantum Hall effects to more exotic cases, like SU(4) fractional quantum Hall effect, and so on.
