2016/04/30 by M. Di Liberto, A. Hemmerich, C. Morais Smith · 1 citation
Physics and Astronomy · #cond-mat.quant-gas #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.117.163001
published as Phys. Rev. Lett. 117, 163001 (2016) · 6+6 pages
arxiv created 2016/10/16 · arxiv updated 2016/10/18
Topological states of matter are peculiar quantum phases showing different edge and bulk transport properties connected by the bulk-boundary correspondence. While non-interacting fermionic topological insulators are well established by now and have been classified according to a ten-fold scheme, the possible realisation of topological states for bosons has not been much explored yet. Furthermore, the role of interactions is far from being understood. Here, we show that a topological state of matter exclusively driven by interactions may occur in the p-band of a Lieb optical lattice filled with ultracold bosons. The single-particle spectrum of the system displays a remarkable parabolic band-touching point, with both bands exhibiting non-negative curvature. Although the system is neither topological at the single-particle level, nor for the interacting ground state, on-site interactions induce an anomalous Hall effect for the excitations, carrying a non-zero Chern number. Our work introduces an experimentally realistic strategy for the formation of interaction-driven topological states of bosons.