Topological Varma Superfluid in Optical Lattices

Year: 2016

Authors: Di Liberto M., Hemmerich A., Smith CM.

Autors Affiliation: Univ Utrecht, Ctr Extreme Matter & Emergent Phenomena, Inst Theoret Phys, Leuvenlaan 4, NL-3584 CE Utrecht, Netherlands; Univ Trento, INO CNR BEC Ctr, I-38123 Povo, Italy; Univ Trento, Dipartimento Fis, I-38123 Povo, Italy; Univ Hamburg, Inst Laser Phys, LuruperChaussee 149, D-22761 Hamburg, Germany; Hamburg Ctr Ultrafast Imaging, LuruperChaussee 149, D-22761 Hamburg, Germany; Zhejiang Univ Technol, Wilczek Quantum Ctr, Hangzhou 310023, Zhejiang, Peoples R China.

Abstract: 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.

Journal/Review: PHYSICAL REVIEW LETTERS

Volume: 117 (16)      Pages from: 163001-1  to: 163001-6

More Information: This work was partially supported by the Netherlands Organization for Scientific Research (NWO), by the German Research Foundation DFG-SFB 925, by the Hamburg centre of ultrafast imaging (CUI), by Provincia Autonoma di Trento, and by the EU-FET Proactive grant AQuS, Project No. 640800. A. H. and C. M. S acknowledge support by NSF-PHYS-1066293 and the hospitality of the Aspen Center for Physics. We are grateful to C. Varma, J. Armaitis, L. Santos, N. Cooper, V. Juricic, Zi Cai, C. Ortix, H. Price, and T. Ozawa for useful discussions. We especially thank N. Lindner for very insightful suggestions and a critical reading of the manuscript.
KeyWords: Copper-oxide Metals; Phase; Transitions; Bands; Model
DOI: 10.1103/PhysRevLett.117.163001

Citations: 46
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