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 | |
| Publication status | Published - 10 Sep 2008 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
Cite this
Probing noise in flux qubits via macroscopic resonant tunneling. / 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.
In: Physical Review Letters, Vol. 101, No. 11, 117003, 10.09.2008.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Probing noise in flux qubits via macroscopic resonant tunneling
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.
PY - 2008/9/10
Y1 - 2008/9/10
N2 - 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.
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
M3 - Article
VL - 101
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 11
M1 - 117003
ER -