Magnetic-field compatibility of SNS transmon qubits

ORAL

Abstract

We present an experimental investigation of the magnetic-field resilience of superconductor-semiconductor-superconductor (SNS) transmon qubits. Our study includes fixed-frequency and gate-tuneable single-junction transmons and flux-tunable, two-junction variants. The clean interface between the InAs nanowires and epitaxially-grown aluminium shells that constitute the Josephson element give these transmons energy relaxation times T$_1$ up to 15 $\mu$s and echo dephasing times T$_{2\mathrm{e}}$ up to 30 $\mu$s at zero field. We track the evolution of transition frequency and coherence at in-plane fields up to 70 mT, using standard spectroscopy and time-domain techniques to identify dominant sources of relaxation and dephasing.

*Research funded by Microsoft Research, the Dutch research organizations FOM and NWO, an ERC Synergy grant, and the Danish National Research Foundation.

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Authors

  • Florian Luthi

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Thijs Stavenga

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Alessandro Bruno

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Christian Dickel

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Nathan Langford

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Adriaan Rol

    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • David Thoen

    • Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Akira Endo

    • Department of Microelectronics and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

  • Thomas Jespersen

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

  • Jesper Nygard

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

  • Peter Krogstrup

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

  • Leonardo DiCarlo

    • QuTech and Kavli Institute of Nanoscience, TU Delft, The Netherlands
    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands
    • QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology and Intel Corporation
    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
    • QuTech and Kavli Institute of Nanoscience, Delft University of Technology