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Observation of two-orbital spin-exchange interactions with ultracold SU(N)-symmetric fermions

Nature Physics volume 10, pages 779784 (2014) | Download Citation

  • A Corrigendum to this article was published on 02 June 2015

This article has been updated

Abstract

Spin-exchanging interactions govern the properties of strongly correlated electron systems such as many magnetic materials. When orbital degrees of freedom are present, spin exchange between different orbitals often dominates, leading to the Kondo effect, heavy fermion behaviour or magnetic ordering. Ultracold ytterbium or alkaline-earth ensembles have attracted much recent interest as model systems for these effects, with two (meta-) stable electronic configurations representing independent orbitals. We report the observation of spin-exchanging contact interactions in a two-orbital SU(N)-symmetric quantum gas realized with fermionic 173Yb. We find strong inter-orbital spin exchange by spectroscopic characterization of all interaction channels and demonstrate SU(N = 6) symmetry within our measurement precision. The spin-exchange process is also directly observed through the dynamic equilibration of spin imbalances between ensembles in separate orbitals. The realization of an SU(N)-symmetric two-orbital Hubbard Hamiltonian opens the route to quantum simulations with extended symmetries and with orbital magnetic interactions, such as the Kondo lattice model.

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Change history

  • 20 May 2015

    In the version of this Article originally published the assignment of states with symmetric electronic wavefunctions (|eg+〉) and with antisymmetric electronic wavefunctions (|eg〉) to the observed spectral lines was inverted throughout. These errors have been corrected online 20 May 2015.

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Acknowledgements

We gratefully acknowledge contributions by C. Schweizer, E. Davis and P. Ketterer during the construction of the experiment, and helpful discussions with A.M. Rey, M. Wall and A. Daley. This work was supported by the EU through the ERC Synergy Grant UQUAM and through the Marie Curie program (fellowship to P.C.D.G.).

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Affiliations

  1. Ludwig-Maximilians-Universität, Schellingstraße 4, 80799 München, Germany

    • F. Scazza
    • , C. Hofrichter
    • , M. Höfer
    • , P. C. De Groot
    • , I. Bloch
    •  & S. Fölling
  2. Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany

    • F. Scazza
    • , C. Hofrichter
    • , M. Höfer
    • , P. C. De Groot
    • , I. Bloch
    •  & S. Fölling

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Contributions

F.S., C.H., M.H., P.C.D.G. and S.F. conceived the experiment, built the set-up, carried out the measurements and analysed the data. All authors contributed extensively to the discussion of the results and to the writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to S. Fölling.

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https://doi.org/10.1038/nphys3061

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