Reducing 1/f flux noise in superconducting devices <i>in situ</i> with UV light.

ORAL

Abstract

Magnetic flux noise with a 1/f power spectrum is pervasive in superconducting devices, and presents a fundamental limit to both the low-frequency energy resolution of dc SQUIDs and the high-frequency coherence of flux-sensitive superconducting qubits. Studies of the scaling of the magnitude of the flux noise with SQUID geometry are consistent with generation of the noise by fluctuating magnetic dipoles on the superconducting surface. Kumar et al. showed that the magnetic dipoles are adsorbed molecular oxygen, and reduced the noise with processes in a room-temperature hermetic sample enclosure. We demonstrate a factor of about three reduction of the 1/f flux noise power spectrum in Nb SQUIDs by applying 240-nm UV light from a Light Emitting Diode at cryogenic temperatures. Subsequent exposure of the SQUIDs to oxygen at atmospheric temperature and pressure restored the flux noise to its original value. Re-exposure to UV at cryogenic temperatures again reduced the flux noise. These results are consistent with molecular oxygen being the source of the noise. Our work demonstrates a practical technique to reduce the flux noise of superconducting devices in situ.

*Funding and support provided by IARPA through the Army Research Office, and LLNL under Contract DE-AC52-07NA27344.

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Presenters

  • Sean O'Kelley

    • Lawrence Livermore Natl Lab

Authors

  • Sean O'Kelley

    • Lawrence Livermore Natl Lab

  • Matthew S Martens

    • Physics, UC Berkeley

  • Steven M Anton

    • Physics, UC Berkeley

  • J S Birenbaum

    • MIT-Lincoln Lab

  • David K Kim

    • MIT Lincoln Laboratory
    • MIT Lincoln Lab
    • MIT-Lincoln Lab
    • MIT Lincoln Laboratories
    • Lincoln Laboratory, Massachusetts Institute of Technology (MIT)
    • Massachusetts Institute of Technology (MIT) Lincoln Laboratory

  • Jonilyn Yoder

    • MIT Lincoln Laboratory
    • MIT-Lincoln Lab
    • Lincoln Laboratory, Massachusetts Institute of Technology (MIT)
    • MIT Lincoln Lab

  • Gene C. Hilton

    • NIST, Boulder
    • NIST Bouder

  • William Oliver

    • Research Laboratory of Electronics, Department of Electrical Engineering and Computer Science, Department of Physics, MIT Lincoln Laboratory, Massachusetts Institute of Techn
    • MIT Lincoln Lab
    • MIT Lincoln Laboratory
    • MIT Lincoln Laboratory, Massachusetts Institute of Technology
    • Department of Physics, Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Lincoln Laboratory, Massachusetts Institute of Technology
    • Research Laboratory of Electronics, Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology MIT
    • Department of Electrical Engineering and Computer Science, Department of Physics, Massachusetts Institute of Technology; MIT Lincoln Laboratory
    • Department of Electrical Engineering and Computer Science, Department of Physics, MIT Lincoln Laboratory, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology
    • Research Laboratory of Electronics, Massachusetts Institute of Technology
    • Research Laboratory of Electronics, Department of Electrical Engineering & Computer Science, Department of Physics, Massachusetts Institute of Technology and MIT Lincoln Labo
    • Physics, MIT
    • MIT-Lincoln Lab
    • MIT Lincoln Laboratories
    • Research Laboratory of Electronics, Department of Physics, Department of Electrical Engineering and Computer Science, Lincoln Laboratory, Massachusetts Institute of Technolog

  • John Clarke

    • Physics, UC Berkeley