Topological Varma Superfluid in Optical Lattices

Topological states of matter are peculiar quantum phases showing different edge and bulk transport properties connected by the bulk-boundary correspondence. While noninteracting fermionic topological insulators are well established by now and have been classified according to a tenfold scheme, the p...

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Bibliographic Details
Published in:Physical review letters 2016-10, Vol.117 (16), p.163001-163001
Main Authors: Di Liberto, M, Hemmerich, A, Morais Smith, C
Format: Article
Language:English
Subjects:
Bosons
Bulk transporters
Curvature
Displays
Ground state
Insulators
Optical lattices
Topology
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Summary:Topological states of matter are peculiar quantum phases showing different edge and bulk transport properties connected by the bulk-boundary correspondence. While noninteracting fermionic topological insulators are well established by now and have been classified according to a tenfold scheme, the possible realization of topological states for bosons has not been explored much 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 nonzero Chern number. Our work introduces an experimentally realistic strategy for the formation of interaction-driven topological states of bosons.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.117.163001