Temporal Fluctuations in the Coherence Parameters of Planar Single-Junction Transmons

ORAL

Abstract

Superconducting qubits have seen improvements in their coherence times to beyond a hundred microseconds. However, reliably reaching the relaxation limit T2=2T1 remains challenging. The decoherence rates vary in time, which makes it difficult to evaluate the device-to-device performance and identify the factors that prevent us from reaching this limit. We experimentally investigate the temporal variations in the relaxation and dephasing rates of a single-Josephson-junction transmon qubit with 〈T1〉≈〈T2〉≈ 75 µs. We gather statistics of the fluctuations of the coherence metrics for different qubit temperatures. The results are analyzed in terms of several known decoherence mechanisms, such as quasiparticles, thermally induced noise via the readout resonator, and interacting two-level systems.

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Presenters

  • Andreas Bengtsson

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

Authors

  • Andreas Bengtsson

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Jonathan Burnett

    Microtechnology and Nanoscience, Chalmers University of Technology

  • Per Delsing

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology

  • Jonas Bylander

    MC2, Chalmers University of Technology, Microtechnology and nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience, Chalmers University of Technology, Microtechnology and Nanoscience (MC2), Chalmers University of Technology