Transport parameterization of single Josephson junction charging effects and coupling energy

ORAL

Abstract

Josephson junctions (JJs) provide the nonlinear inductance in superconducting qubits where the qubit resonance frequency depends on the Josephson energy E_J and charging energy E_C of the junction. In the widely used transmon configuration, E_J>>E_C in order to minimize the sensitivity of the qubit to charge noise. We report here low-frequency transport measurements on single Al test JJs as well as JJs in transmons. We observe charging effects in the IV curves of junctions made with bridgeless evaporation techniques. In contrast, JJs fabricated with the Dolan bridge technique do not show charging effects. Additionally, we observe large switching currents in Dolan junctions compared to bridgeless junctions with similar characteristics, suggesting that the fabrication technique may play a role in the qubit's susceptibility to charge noise and in qubit coherence times.

* SQMS Grant 60058097

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Presenters

  • Yanpei Deng

    Northwestern University

Authors

  • Maxwell Wisne

    Northwestern University

  • Yanpei Deng

    Northwestern University

  • Venkat Chandrasekhar

    Northwestern University

  • Mustafa Bal

    Fermilab, Fermi National Accelerator Laboratory

  • Francesco Crisa

    Fermi National Accelerator Laboratory, Illinois Institute of Technology, Fermilab, Illinois Institute of Technology

  • Anna Grassellino

    Fermilab, Fermi National Accelerator Laboratory

  • Cameron J Kopas

    Rigetti Quantum Computing, Rigetti Computing, Inc.

  • Josh Y Mutus

    Rigetti Computing, Inc., Rigetti Quantum Computing, Rigetti Computing Inc

  • Hilal Cansizoglu

    Rigetti Computing, Rigetti Computing, Inc.

  • Florent Lecocq

    National Institute of Standards and Technology Boulder, National Institute of Standards and Technology, Boulder, National Institute of Standards and Technology

  • José Aumentado

    National Institute of Standards and Technology, Boulder, National Institute of Standards and Technology Boulder, National Institute of Standards and Technology, Quantum Circuits, Inc, Quantum Circuits, Inc.

  • Stephen T Gill

    National Institute of Standards and Technology, Boulder, National Institute of Standards and Technology