Probing Temperature Dependent Noise in Flux Qubits via Macroscopic Resonant Tunneling

ORAL

Abstract

Macroscopic resonant tunneling between the two lowest lying states of a bistable RF-SQUID is used to characterize flux noise in a potential qubit. Detailed measurements of incoherent decay rates as a function of flux bias revealed that the Gaussian shaped tunneling rate is not peaked at the resonance point, but is shifted to a flux bias at which the initial well is higher than the target well. This observation indicates that the dominant low frequency (1/f) flux noise in this device is quantum mechanical in nature. The r.m.s. amplitude of the noise, which is proportional to decoherence rate 1/T$^{*}_{2}$, was observed to be weakly dependent on temperature below 70 mK.

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Authors

  • J. Johansson

  • P. Bunyk

  • S. Govorkov

  • M.C. Thom

  • S. Uchaikin

  • C.J.S. Truncik

  • A.J. Berkley

  • R. Harris

  • M.W. Johnson

  • M.H.S. Amin

    • D-Wave Systems Inc., 100-4401 Still Creek Dr., Burnaby, BC V5C 6G9, Canada

  • S. Han

    • Department of Physics and Astronomy, University of Kansas, Lawrence KS, USA

  • B. Bumble

  • A. Fung

  • A. Kaul

  • A. Kleinsasser

    • Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA, USA

  • D.V. Averin

    • Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook NY, USA