Cavity-induced decoherence in a long-lived superconducting flux qubit

ORAL

Abstract

We implement a circuit QED system with a capacitively shunted (C-shunt) flux qubit coupled to a transmission line resonator. The improved design substantially enhances qubit coherences, achieving T1 of 55us at degeneracy. Dephasing is also improved, giving a spin-echo decay of 40us. We found that the dephasing is limited by photon shot noise at a residual thermal photon population of 0.006. The driven-evolution T1rho-spectroscopy and free-evolution CPMG results both validate the finding.

*The Lincoln Laboratory portion of this work was sponsored by the Asst. Secretary of Defense for Research \& Engineering under Air Force Contract number FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the author.

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Authors

  • Fei Yan

    • Research Laboratory for Electronics, Massachusetts Institute of Technology

  • Archana Kamal

    • Research Laboratory for Electronics, Massachusetts Institute of Technology

  • Theodore Gudmundsen

    • MIT Lincoln Laboratory

  • Jonilyn Yoder

    • MIT Lincoln Laboratory

  • Simon Gustavsson

    • MIT Lincoln Laboratory; Research Laboratory for Electronics, Massachusetts Institute of Technology

  • William Oliver

    • Research Laboratory for Electronics, Massachusetts Institute of Technology