Design and measurement of improved capacitively-shunted flux qubits

ORAL

Abstract

The addition of a capacitive or inductive shunt across one of the junctions can alter the coherence properties of a classic flux or RF-SQUID qubit. We have studied the performance of capacitively shunted flux qubits fabricated with MBE aluminum[1], starting from a 2D coplanar waveguide geometry used in similar high-performance transmon qubits, and measured dispersively. We will detail the importance of design parameters that preserve the flux qubit's anharmonicity and discuss conclusions about materials quality based on calculations of the participation of junction, dielectric, and superconductor components. This research was funded in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA); and by the Assistant Secretary of Defense for Research \& Engineering under Air Force Contract number FA8721-05-C-0002. All statements of fact, opinion or conclusions contained herein are those of the authors and should not be construed as representing the official views or policies of IARPA, the ODNI, or the U.S. Government \\[4pt] [1] Megrant et al., APL 100, 113510 (2012).

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Authors

  • Adam Sears

    MIT Lincoln Laboratory

  • Jeffrey Birenbaum

    University of California Berkeley

  • David Hover

    MIT Lincoln Laboratory

  • Theodore Gudmundsen

    MIT Lincoln Laboratory

  • Andrew Kerman

    MIT Lincoln Laboratory

  • Paul Welander

    MIT Lincoln Laboratory

  • Jonilyn L. Yoder

    MIT Lincoln Laboratory

  • Simon Gustavsson

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

  • Xiaoyue Jin

    Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, Research Laboratory of Electronics, Massachusetts Institute of Technology

  • Archana Kamal

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

  • John Clarke

    Department of Physics, University of California, Berkeley, University of California, Berkeley, Dale Van Harlingen, University of Illinois at Urbana-Champaign, University of California Berkeley

  • William Oliver

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