Mach-Zehnder-type Interferometry in a Strongly Driven Persistent-Current Qubit

ORAL

Abstract

We have demonstrated Mach-Zehnder-type interferometry with a niobium superconducting persistent-current qubit. The qubit’s ground and first-excited states exhibit an anti-crossing. Driving the qubit with a large-amplitude harmonic excitation sweeps it through this anti-crossing two times per period. The induced Landau-Zener (LZ) transitions act as coherent beamsplitters, and the accumulated phase between LZ transitions varies with the driving amplitude. We have observed quantum interference fringes as a function of the driving amplitude for 1 to 20 photon excitations. We present and discuss these results.

*This work at was supported by the AFOSR (F49620-01-1-0457) under the DURINT program and the DoD under Air Force contract FA8721-05-C-0002.

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Authors

  • William Oliver

    • MIT Lincoln Laboratory
    • MIT Lincoln Laboratories

  • Yang Yu

    • MIT EECS Department

  • Janice Lee

    • MIT EECS Department

  • Karl Berggren

    • MIT EECS Department
    • Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology

  • Leonid Levitov

    • MIT
    • MIT Physics Department

  • Terry Orlando

    • MIT
    • MIT EECS Department