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Parity switching in a semiconductor-based transmon qubit

ORAL

Abstract

Unpaired quasiparticles can adversely affect the performance of superconducting devices, including qubits based on Majorana zero modes. We study charge parity switching in a superconductor-semiconductor nanowire-based transmon device that shows Little-Parks oscillations of its frequency as a function of magnetic field. In the recovery regime, where a single flux quantum threads the cross-section of the wire transport measurements recently revealed signatures compatible with Majorana zero modes [1].
We read out the charge parity by dispersive monitoring of a readout resonator to which the transmon qubit is coupled. At zero magnetic field, we measure parity switching times in the range of 10-100 ms. As the magnetic field is increased toward the first closing of the superconducting gap, the switching time is decreased and is consistent with the superconducting gap reduction. In the recovery regime where the gap is re-opened, the switching time is reduced below the sensitivity of our measurement, putting a bound on the minimum observable Majorana hybridization energy in a full-shell nanowire system.

[1] S. Vaitiekenas et al., Flux-induced Majorana modes in full-shell nanowires, arXiv:1809.05513 (2018)

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Presenters

  • Deividas Sabonis

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen

Authors

  • Deividas Sabonis

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen

  • Oscar Erlandsson

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen

  • Anders Kringhøj

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen

  • Bernard Van Heck

    Microsoft Quantum Lab Delft, Delft University of Technology, 2600 GA Delft, The Netherlands, Microsoft, Quantum Lab Delft, Microsoft, Microsoft Quantum Lab Delft

  • Thorvald Larsen

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Microsoft

  • Torsten Karzig

    Microsoft

  • Dmitry I. Pikulin

    Microsoft Station Q, University of California, Microsoft Quantum, Microsoft Station Q, University of California, Santa Barbara, Microsoft, Microsoft Research

  • Peter Krogstrup

    Microsoft Quantum Materials Lab and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Kanalvej 7, 2800 Kongens Lyngby, Denmark, Microsoft, Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen and Microsoft Quantum Materials Lab Copenhagen, Quantum Materials Lab Copenhagen, Microsoft, Center for Quantum Devices and Microsoft Quantum Lab–Copenhagen, Center for Quantum Devices and Microsoft Quantum Lab Copenhagen, Niels Bohr Institute, University of Copenhagen, Microsoft Corp

  • Karl Petersson

    Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Microsoft, Niels Bohr Inst, Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark

  • Charles Marcus

    Center for Quantum Devices and Microsoft Quantum Lab Copenhagen, Niels Bohr Institute, University of Copenhagen, Microsoft Quantum Lab Copenhagen and Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark, Univ of Copenhagen, Center for Quantum Devices and Microsoft Quantum Lab - Copenhagen, University of Copenhagen, Center for Quantum Devices, Microsoft Quantum Lab – Copenhagen and Niels Bohr Institute, University of Copenhagen, Microsoft Corp, Niels Bohr Institute, University of Copenhagen