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ABSTRACT Sixty years ago, Karplus and Luttinger pointed out that quantum particles moving on a lattice could acquire an anomalous transverse velocity in response to a force, providing an

explanation for the unusual Hall effect in ferromagnetic metals1. A striking manifestation of this transverse transport was then revealed in the quantum Hall effect2 where the plateaux

depicted by the Hall conductivity were attributed to a topological invariant characterizing the Bloch bands: the Chern number3. Until now, topological transport associated with non-zero

Chern numbers has only been observed in electronic systems2,4,5. Here we use the transverse deflection of an atomic cloud in response to an optical gradient to measure the Chern number of

artificially generated Hofstadter bands6. These topological bands are very flat and thus constitute good candidates for the realization of fractional Chern insulators7. Combining these

deflection measurements with the determination of the band populations, we obtain an experimental value for the Chern number of the lowest band _ν_exp = 0.99(5). This first Chern-number

measurement in a non-electronic system is facilitated by an all-optical artificial gauge field scheme, generating uniform flux in optical superlattices. Access through your institution Buy

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OTHERS ENGINEERING NON-HERMITIAN SKIN EFFECT WITH BAND TOPOLOGY IN ULTRACOLD GASES Article Open access 13 October 2022 REALIZATION OF AN ANOMALOUS FLOQUET TOPOLOGICAL SYSTEM WITH ULTRACOLD

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al. Experimental realisation of the topological Haldane model. Preprint at http://arXiv.org/abs/1406.7874 (2014) Download references ACKNOWLEDGEMENTS We acknowledge fruitful discussions with

J. Dalibard and also with A. Dauphin, P. Gaspard, F. Gerbier, F. Grusdt, I. Carusotto, T. Ozawa and H. Price. This work was supported by NIM, the EU (UQUAM, SIQS) and EPSRC Grant No.

EP/K030094/1. M.Aidelsburger was further supported by the Deutsche Telekom Stiftung, M.L. by ExQM and N.G. by the Université Libre de Bruxelles and the FRS-FNRS (Belgium). AUTHOR INFORMATION

Author notes * J. T. Barreiro Present address: Present address: Department of Physics, University of California, San Diego, California 92093, USA., AUTHORS AND AFFILIATIONS * Fakultät für

Physik, Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 München, Germany M. Aidelsburger, M. Lohse, C. Schweizer, M. Atala, J. T. Barreiro & I. Bloch * Max-Planck-Institut für

Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany M. Aidelsburger, M. Lohse, C. Schweizer, M. Atala, J. T. Barreiro & I. Bloch * Collège de France, 11 place Marcelin

Berthelot & Laboratoire Kastler Brossel, CNRS, UPMC, ENS, 24 rue Lhomond 75005 Paris, France, S. Nascimbène & N. Goldman * T. C. M. Group, Cavendish Laboratory, J.J. Thomson Avenue,

Cambridge CB3 0HE, UK N. R. Cooper * Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles (U.L.B.), B-1050 Brussels, Belgium N. Goldman Authors * M. Aidelsburger

View author publications You can also search for this author inPubMed Google Scholar * M. Lohse View author publications You can also search for this author inPubMed Google Scholar * C.

Schweizer View author publications You can also search for this author inPubMed Google Scholar * M. Atala View author publications You can also search for this author inPubMed Google Scholar

* J. T. Barreiro View author publications You can also search for this author inPubMed Google Scholar * S. Nascimbène View author publications You can also search for this author inPubMed 

Google Scholar * N. R. Cooper View author publications You can also search for this author inPubMed Google Scholar * I. Bloch View author publications You can also search for this author

inPubMed Google Scholar * N. Goldman View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS M.Aidelsburger, M.L. and C.S. performed the

experiment. All authors contributed to the design of the experiment, the theoretical and data analysis, and to the writing of the paper. I.B. and N.G. supervised the project. CORRESPONDING

AUTHOR Correspondence to M. Aidelsburger. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION

Supplementary Information (PDF 1120 kb) RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Aidelsburger, M., Lohse, M., Schweizer, C. _et al._ Measuring the

Chern number of Hofstadter bands with ultracold bosonic atoms. _Nature Phys_ 11, 162–166 (2015). https://doi.org/10.1038/nphys3171 Download citation * Received: 24 July 2014 * Accepted: 30

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