Hard-core bosons in one-dimensional interacting topological bands

Abstract

We study the hard-core bosons in one-dimensional (1D) interacting topological bands at different filling factors using exact diagonalization. At the filling factor $\nu=1$ and in the presence of on-site Hubbard interaction, we find no sign of the existence of the bosonic topological phase, which is in contrast to the fermionic case. Instead by studying the momentum distribution and the condensate fraction we find a superfluid (SF) to Mott-insulator transition driven by the Hubbard interaction. At the filling factor $\nu=1/3$ and in the presence of longer-ranged interactions, we identify the bosonic fractional topological phase (FTP) whose ground-states are characterized by the three-fold degeneracy and quantized total Berry phase, which is very similar to the fermionic case. Finally we discuss the reason of the different behaviors of hard-core bosons at different filling factors by mapping them to spinless fermions. Our these results can be realized in cold-atom experiments.Comment: PHYSICAL REVIEW A 86, 055604 (2012), brief repor

Topological bosonic states on ribbons of a honeycomb lattice

“…In this way, a topological Bose-Mott insulator in a onedimensional (1D) optical superlattice has been identified [12][13][14][15]. However this approach often fails for higher dimensions, or even quasi-1D systems (such as in the ladder geometry) [16,17]. The reason is that in strictly 1D open lattices, hardcore bosons behaves exactly the same as fermions due to the absence of particle exchange process, however, the commutation statistics of bosons breaks the topological phase when the exchange is possible for dimensions beyond strictly 1D.…”