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Quantum Fluctuations in Josephson Junction Comparators

Thomas J. Walls·Timur V. Filippov·Konstantin K. Likharev
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Abstract

We have developed a method for calculation of quantum fluctuation effects, in particular of the uncertainty zone developing at the potential curvature sign inversion, for a damped harmonic oscillator with arbitrary time dependence of frequency and for arbitrary temperature, within the Caldeira-Leggett model. The method has been applied to the calculation of the gray zone width Delta Ix of Josephson-junction balanced comparators driven by a specially designed low-impedance RSFQ circuit. The calculated temperature dependence of Delta Ix in the range 1.5 to 4.2K is in a virtually perfect agreement with experimental data for Nb-trilayer comparators with critical current densities of 1.0 and 5.5 kA/cm^2, without any fitting parameters.

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Thomas J. Walls, Timur V. Filippov, Konstantin K. Likharev. 2002-07-15. Quantum Fluctuations in Josephson Junction Comparators. https://doi.org/10.1103/physrevlett.89.217004

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