An extended Josephson junction intrinsically couples the superconducting current to the microwave cavity in the insulating barrier. We demonstrate that this coupling produces sidebands in the microwave cavity resonances of the junction. By measuring the switching current distribution, we show that microwave radiation at sidebands brings the Josephson phase out of equilibrium. In particular, the effective phase temperature is reduced or enhanced through anti-Stokes and Stokes scattering, respectively. Phase cooling and heating both increase with microwave power.An extended Josephson junction intrinsically couples the superconducting current to the microwave cavity in the insulating barrier. We demonstrate that this coupling produces sidebands in the microwave cavity resonances of the junction. By measuring the switching current distribution, we show that microwave radiation at sidebands brings the Josephson phase out of equilibrium. In particular, the effective phase temperature is reduced or enhanced through anti-Stokes and Stokes scattering, respectively. Phase cooling and heating both increase with microwave power.

arXiv:1010.5983Oct 28, 20100 citations

Observation of Transition from Escape Dynamics to Underdamped Phase Diffusion in a Josephson Junction

Jani M. Kivioja, T. E. Nieminen, Julien Claudon +3 more

We have investigated the dynamics of underdamped Josephson junctions with a relatively small Josephson coupling ${E}_{J}$ . In addition to the usual crossover between macroscopic quantum tunneling and thermally activated (TA) behavior we observe, for the first time, the transition from TA behavior to underdamped phase diffusion. Above the crossover temperature, the threshold for switching into the finite-voltage state becomes extremely sharp. We propose a ( $T$ , ${E}_{J}$ ) phase diagram with various regimes and show that for a proper description of it, dissipation and level quantization in a metastable well are crucial.We have investigated the dynamics of underdamped Josephson junctions with a relatively small Josephson coupling ${E}_{J}$. In addition to the usual crossover between macroscopic quantum tunneling and thermally activated (TA) behavior we observe, for the first time, the transition from TA behavior to underdamped phase diffusion. Above the crossover temperature, the threshold for switching into the finite-voltage state becomes extremely sharp. We propose a ($T$, ${E}_{J}$) phase diagram with various regimes and show that for a proper description of it, dissipation and level quantization in a metastable well are crucial.

arXiv:cond-mat/0501383Physical Review LettersJun 22, 200590 citations

Time Domain Analysis of Dynamical Switching in a Josephson Junction

Joachim Sjöstrand, T. H. Hansson, A. Karlhede +2 more

Springer eBooksMay 29, 20062 citations

Study of Phase Dynamics in Moderately Damped Josephson Junctions

D. Massarotti, Luigi Longobardi, D. Stornaiuolo +5 more

Journal of Superconductivity and Novel MagnetismDec 29, 20122 citations

Resonant switching current detector based on underdamped Josephson junctions

V. M. Krasnov

Current-biased Josephson junctions can act as detectors of electromagnetic radiation. At optimal conditions, their sensitivity is limited by fluctuations causing stochastic switching from the superconducting to the resistive state. This work provides a quantitative description of a stochastic switching current detector, based on an underdamped Josephson junction. It is shown that activation of a Josephson plasma resonance can greatly enhance the detector responsivity in proportion to the quality factor of the junction. The ways of tuning the detector for achieving optimal operation are discussed. For realistic parameters of Nb / Al O x / Nb tunnel junctions, the sensitivity and noise-equivalent power (NEP) can reach values of S ≃ 5 × 10 12 (V/W) and NEP ≃ 2 × 10 − 23 ( WHz − 1 / 2 ), respectively. These outstanding characteristics facilitate both bolometric and single-photon detection in microwave and terahertz ranges. Published by the American Physical Society 2024Current-biased Josephson junctions can act as detectors of electromagnetic radiation. At optimal conditions, their sensitivity is limited by fluctuations causing stochastic switching from the superconducting to the resistive state. This work provides a quantitative description of a stochastic switching current detector, based on an underdamped Josephson junction. It is shown that activation of a Josephson plasma resonance can greatly enhance the detector responsivity in proportion to the quality factor of the junction. The ways of tuning the detector for achieving optimal operation are discussed. For realistic parameters of Nb / Al O x / Nb tunnel junctions, the sensitivity and noise-equivalent power (NEP) can reach values of S ≃ 5 × 10 12 (V/W) and NEP ≃ 2 × 10 − 23 ( WHz − 1 / 2 ), respectively. These outstanding characteristics facilitate both bolometric and single-photon detection in microwave and terahertz ranges. Published by the American Physical Society 2024

arXiv:2403.03803Physical Review AppliedAug 6, 20249 citations

We have investigated the dynamics of underdamped Josephson junctions with a relatively small Josephson coupling

{E}_{J}

. In addition to the usual crossover between macroscopic quantum tunneling and thermally activated (TA) behavior we observe, for the first time, the transition from TA behavior to underdamped phase diffusion. Above the crossover temperature, the threshold for switching into the finite-voltage state becomes extremely sharp. We propose a (

T

{E}_{J}

) phase diagram with various regimes and show that for a proper description of it, dissipation and level quantization in a metastable well are crucial.