Exchange interaction between distant spins mediated by a multielectron quantum dot

ORAL

Abstract

We demonstrate coherent exchange interactions between two separated electron spins in a GaAs heterostructure, mediated by a central multielectron quantum dot. We observe three different regimes of spin exchange. First, long-range superexchange, mediated my virtual occupations of the multielectron dot. Second, direct exchange, induced by moving one of the electrons onto the multielectron dot. Finally, on-site exchange, with both electrons transferred to the multielectron dot. Using independent readout of both spins, we further show that this interaction mechanism can be used for a fast and high-fidelity square-root-SWAP entangling gate for single electronic spins.

*Support through LPS-MPO-CMTC, Army Research Office, the Danish National Research Foundation, and the Danish Innovation Fund is acknowledged.

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Authors

  • F. K. Malinowski

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark

  • F. Martins

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark

  • P. D. Nissen

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark

  • C. M. Marcus

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark

  • F. Kuemmeth

    • Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Denmark

  • G. C. Gardner

    • Department of Physics and Astronomy, Birck Nanotechnology Center, and Station Q Purdue, Purdue University, USA

  • S. Fallahi

    • Department of Physics and Astronomy, Birck Nanotechnology Center, and Station Q Purdue, Purdue University, USA

  • M. J. Manfra

    • Department of Physics and Astronomy, Birck Nanotechnology Center, and Station Q Purdue, Purdue University, USA

  • T. Smith

    • Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Australia

  • A. C. Doherty

    • Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Australia

  • S. D. Bartlett

    • Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, Australia