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Enhancement of Josephson phase diffusion by microwaves

Y. Koval·M. V. Fistul·A. V. Ustinov
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Abstract

We report an experimental and theoretical study of the phase diffusion in small Josephson junctions under microwave irradiation. A peculiar enhancement of the phase diffusion by microwaves is observed. The enhancement manifests itself by a pronounced current peak in the current-voltage characteristics. The voltage position $V_{\rm top}$ of the peak increases with the power $P$ of microwave radiation as $V_{\rm top}\propto\sqrt P$, while its current amplitude weakly decreases with $P$. As the microwave frequency increases, the peak feature evolves into Shapiro steps with finite slope. Our theoretical analysis taking into account the enhancement of incoherent superconducting current by multi-photon absorption is in good agreement with experimental data.

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Y. Koval, M. V. Fistul, A. V. Ustinov. 2004-06-29. Enhancement of Josephson phase diffusion by microwaves. https://doi.org/10.1103/physrevlett.93.087004

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