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Effect of external high-energy radiation on coherence of superconducting qubits

ORAL

Abstract

There is an anomalously high density of broken Cooper pairs in superconductors, which has been universally seen in experiments. It has been shown that external radiation can break Cooper pairs in superconducting circuits, causing elevated quasi-particle densities. The origin of the radiation has been a source of extensive research over several decades, but no conclusive answer has been found. It is known that thermal effects cause a finite quasi-particle density, but the observed densities are several orders of magnitudes higher than predicted by thermal equilibrium model. In superconducting devices infrared photons have shown to contribute to non-equilibrium quasi-particle densities through connected microwave lines. We propose that in addition to this effect, gamma-rays from radioactive decays in the environment are also a significant source of quasi-particle breaking radiation. We have measured the strength of the external radiation in our laboratory and demonstrated the effect of the high-energy radiation on qubit coherence using a Cu64 source with time-varying intensity. We show that proper shielding from gamma-rays is required for reaching high coherence times in transmon qubits.

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Presenters

  • Antti Vepsalainen

    Research Laboratory of Electronics, Massachusetts Institute of Technology, Research Laboratory of Electronics, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MIT

Authors

  • Antti Vepsalainen

    Research Laboratory of Electronics, Massachusetts Institute of Technology, Research Laboratory of Electronics, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MIT

  • Amir Karamlou

    Massachusetts Institute of Technology MIT, Research Laboratory of Electronics, Massachusetts Institute of Technology MIT

  • John Laurence Orrell

    Pacific Northwest National Laboratory

  • Akshunna S Dogra

    Massachusetts Institute of Technology MIT

  • Fransisca Vasconcelos

    Massachusetts Institute of Technology MIT

  • Ben Loer

    Pacific Northwest National Laboratory

  • Bethany Niedzielski

    MIT Lincoln Laboratory

  • Alexander Melville

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

  • 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

  • Mollie Schwartz

    MIT Lincoln Laboratory, MIT Lincoln Lab

  • Jonilyn Yoder

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

  • Brent A VanDevender

    Pacific Northwest National Laboratory

  • Simon Gustavsson

    Research Laboratory of Electronics, Massachusetts Institute of Technology, Research Laboratory of Electronics, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology MIT, Massachusetts Institute of Technology, Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT)

  • 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