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Charge echo in a Cooper-pair box

Y. Nakamura·Yu. A. Pashkin·T. Yamamoto·J. S. Tsai
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Abstract

A spin-echo-type technique is applied to an artificial two-level system that utilizes charge degree of freedom in a small superconducting electrode. Gate-voltage pulses are used to produce the necessary pulse sequence in order to eliminate the inhomogeneity effect in the time-ensemble measurement and to obtain refocused echo signals. Comparison of the decay time of the observed echo signal with estimated decoherence time suggests that low-frequency energy-level fluctuations due to the 1/f charge noise dominate the dephasing in the system.

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Y. Nakamura, Yu. A. Pashkin, T. Yamamoto, J. S. Tsai. 2001-11-21. Charge echo in a Cooper-pair box. https://doi.org/10.1103/physrevlett.88.047901

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