Effects of smooth boundaries on topological edge modes in optical lattices

Buchhold, Michael, Cocks, Daniel, and Hofstetter, Walter (2012) Effects of smooth boundaries on topological edge modes in optical lattices. Physical Review A (Atomic, Molecular and Optical Physics), 85. 063614. pp. 1-12.

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Since the experimental realization of synthetic gauge fields for neutral atoms, the simulation of topologically nontrivial phases of matter with ultracold atoms has become a major focus of cold-atom experiments. However, several obvious differences exist between cold-atom and solid-state systems, for instance the small size of the atomic cloud and the smooth confining potential. In this article we show that sharp boundaries are not required to realize quantum Hall or quantum spin Hall physics in optical lattices and, on the contrary, that edge states in a smooth confinement exhibit additional interesting properties, such as spatially resolved splitting and merging of bulk bands and the emergence of robust auxiliary states in bulk gaps to preserve the topological quantum numbers. In addition, we numerically validate that these states are robust against disorder. Finally, we analyze possible detection methods, with a focus on Bragg spectroscopy, to demonstrate that the edge states can be detected and that Bragg spectroscopy can reveal how topological edge states are connected to the different bulk bands.

Item ID: 34728
Item Type: Article (Research - C1)
ISSN: 1094-1622
Funders: German National Academic Foundation, Stiftung Polytechnische Gesellschaft Frankfurt am Main, German Research Foundation (DFG)
Projects and Grants: DFG Sonderforschungsbereich SFB-TR/49, DFG Forschergruppe FOR 801
Date Deposited: 24 Sep 2014 02:45
FoR Codes: 02 PHYSICAL SCIENCES > 0204 Condensed Matter Physics > 020499 Condensed Matter Physics not elsewhere classified @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%
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