Jellybean quantum dots in silicon for qubit coupling

ORAL

Abstract

The small size and excellent integrability of silicon metal-oxide-semiconductor (SiMOS) quantum dot spin qubits make them an attractive system for mass-manufacturable, scaled-up quantum processors. Furthermore, classical control electronics can be integrated on-chip, in-between the qubits, if an architecture with sparse arrays of qubits is chosen. In such an architecture qubits are either transported across the chip via shuttling, or coupled via mediating quantum systems over short-to-intermediate distances. In this presentation, we will report on the charge and spin characteristics of an elongated quantum dot – a so-called jellybean quantum dot – for the prospects of acting as a qubit-qubit coupler. Charge transport, charge sensing and magneto-spectroscopy measurements are performed on a SiMOS quantum dot device at mK temperature, and compared to Hartree-Fock multielectron simulations. At low electron occupancies where disorder effects and strong electron-electron interaction dominate over the electrostatic confinement potential, the data reveals the formation of three coupled dots, akin to a tunable, artificial molecule. One dot is formed centrally under the gate and two are formed at the edges. At high electron occupancies, these dots merge into one large dot with well-defined spin states, verifying that jellybean dots have the potential to be used as qubit couplers in future quantum computing architectures.

*We acknowledge support from the Australian Research Council (FL190100167, CE170100012 and LE160100069), the US Army Research Office (W911NF-17-1-0198), the NSW Node of the Australian National Fabrication Facility and UNSW Sydney. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Office or the US Government. The US Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. Z.W., M.K.F., S.S., W.G., J.Y.H., Y.S. acknowledge support from the Sydney Quantum Academy. A.L. acknowledges support through the UNSW Scientia program. A.S.D. is CEO and a director of Diraq Pty Ltd.

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Publication: Z. Wang, et al., Jellybean quantum dots in silicon for qubit coupling and on-chip quantum chemistry, arXiv:2208.04724 (2022)

Presenters

  • Arne Laucht

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales
    • University of New South Wales, Diraq Pty. Ltd.

Authors

  • Arne Laucht

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales
    • University of New South Wales, Diraq Pty. Ltd.

  • Zeheng Wang

    • University of New South Wales

  • Santiago Serrano

    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales

  • MengKe Feng

    • University of New South Wales
    • 1) University of New South Wales

  • William Gilbert

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.

  • Ross Leon

    • Quantum Motion
    • University of New South Wales

  • Tuomo I Tanttu

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales 2) Diraq
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.

  • Philip Mai

    • University of New South Wales

  • Dylan Liang

    • University of New South Wales

  • Yue Y Huang

    • UNSW
    • 1) University of New South Wales
    • University of New South Wales

  • Yue Su

    • University of New South Wales

  • Wee Han Lim

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales

  • Fay E Hudson

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales

  • Christopher Escott

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.

  • Andrea Morello

    • University of New South Wales

  • Henry Yang

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • UNSW Sydney

  • Andrew S Dzurak

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • University of New South Wales
    • University of New South Wales, Diraq Pty. Ltd.

  • Andre Saraiva

    • 1) University of New South Wales, 2) Diraq Pty. Ltd
    • 1) University of New South Wales, 2) Diraq Pty. Ltd.
    • UNSW Sydney
    • UNSW
    • Diraq
    • University of New South Wales, Diraq Pty. Ltd.