Probing noise in flux qubits via macroscopic resonant tunneling

R. Harris; M. W. Johnson; S. Han; A. J. Berkley; J. Johansson; P. Bunyk; E. Ladizinsky; S. Govorkov; M. C. Thom; S. Uchaikin; B. Bumble; A. Fung; A. Kaul; A. Kleinsasser; M. H.S. Amin; D. V. Averin

doi:10.1103/PhysRevLett.101.117003

Probing noise in flux qubits via macroscopic resonant tunneling

R. Harris
, M. W. Johnson
, S. Han
, A. J. Berkley
, J. Johansson
, P. Bunyk
, E. Ladizinsky
, S. Govorkov
, M. C. Thom
, S. Uchaikin
, B. Bumble
, A. Fung
, A. Kaul
, A. Kleinsasser
, M. H.S. Amin
, D. V. Averin

Physics and Astronomy

Stony Brook University

Research output: Contribution to journal › Article › peer-review

73 Scopus citations

Abstract

Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate 1/τφ, was observed to be weakly dependent on temperature below 70mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium.

Original language	English
Article number	117003
Journal	Physical Review Letters
Volume	101
Issue number	11
DOIs	https://doi.org/10.1103/PhysRevLett.101.117003
State	Published - Sep 10 2008

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10.1103/PhysRevLett.101.117003

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Harris, R., Johnson, M. W., Han, S., Berkley, A. J., Johansson, J., Bunyk, P., Ladizinsky, E., Govorkov, S., Thom, M. C., Uchaikin, S., Bumble, B., Fung, A., Kaul, A., Kleinsasser, A., Amin, M. H. S., & Averin, D. V. (2008). Probing noise in flux qubits via macroscopic resonant tunneling. Physical Review Letters, 101(11), Article 117003. https://doi.org/10.1103/PhysRevLett.101.117003

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title = "Probing noise in flux qubits via macroscopic resonant tunneling",

abstract = "Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate 1/τφ, was observed to be weakly dependent on temperature below 70mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium.",

author = "R. Harris and Johnson, \{M. W.\} and S. Han and Berkley, \{A. J.\} and J. Johansson and P. Bunyk and E. Ladizinsky and S. Govorkov and Thom, \{M. C.\} and S. Uchaikin and B. Bumble and A. Fung and A. Kaul and A. Kleinsasser and Amin, \{M. H.S.\} and Averin, \{D. V.\}",

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AU - Harris, R.

AU - Johnson, M. W.

AU - Han, S.

AU - Berkley, A. J.

AU - Johansson, J.

AU - Bunyk, P.

AU - Ladizinsky, E.

AU - Govorkov, S.

AU - Thom, M. C.

AU - Uchaikin, S.

AU - Bumble, B.

AU - Fung, A.

AU - Kaul, A.

AU - Kleinsasser, A.

AU - Amin, M. H.S.

AU - Averin, D. V.

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AB - Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate 1/τφ, was observed to be weakly dependent on temperature below 70mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium.

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U2 - 10.1103/PhysRevLett.101.117003

DO - 10.1103/PhysRevLett.101.117003

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JO - Physical Review Letters

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Probing noise in flux qubits via macroscopic resonant tunneling

Abstract

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