Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. B, Condensed matter

Coherence of a pair of coupled Josephson weak links

A. S. Deakin, M. A. H. Nerenberg

Published Jun 1, 1983• 2 citations
Publisher

Abstract

The coherence of the microwave power emitted by two coupled Josephson weak links is calculated from an analytical treatment of the resistively shunted junction model. The results are discussed in the light of previous numerical work and experiments.
DOI
10.1103/physrevb.27.6954

Related papers

Nonlinear microwave absorption in weak-link Josephson junctions

Lei Xie, Jarek Wosik, John C. Wolfe

A model, based on the resistively shunted junction theory, is developed and used to study microwave absorption in weak-link Josephson junctions in high-${T}_{c}$ superconductors. Both linear and nonlinear cases of microwave absorption in Josephson junctions are analyzed. A comparison of the model with microwave absorption loop theory is presented along with a general condition for the applicability of both models. The nonlinear case was solved numerically and the threshold points of sharp microwave absorption are presented. At these points, a $2\ensuremath{\pi}$ phase quantization takes place within each microwave cycle, leading to an onset of a sharp rise of absorption. Existence of the $2\ensuremath{\pi}$ dynamic quantization is the key to the interpretation of nonlinear microwave absorption data. The nonlinear microwave absorption model is extended to the study of nonuniformly coupled junctions, and a general statement for the applicability of such a model is presented.

Physical review. B, Condensed matter•Dec 1, 1996•21 citations

Microwave impedance of superconducting weak links

J. D. Franson, James E. Mercereau

Calibrated measurements of both the real and imaginary parts of the microwave impedance of proximity coupled superconducting weak links have been made. The measurements were compared with analytic calculations based on several different models for the supercurrent Is and quasiparticle current. For dc bias currents I1 less than the critical current Ic, the experimental results are consistent with the Josephson relation Is=Ic sinφ, where φ is the quantum phase angle. However, for I1≳Ic, the Fourier component of Is at the Josephson frequency is found to be significantly less (∼0.65±0.1) than would be predicted from Is=Ic sinφ, and consistent with Tinkham’s analysis of a phase slip process. The experimental results indicate that the phase-dependent part of the quasiparticle current, if it exists at all, is no more than 10% of the total quasiparticle current. These results do not necessarily contradict previous measurements made on true tunnel junctions because of the fundamental differences between the two types of devices.

Journal of Applied Physics•Jul 1, 1976•17 citations

High-frequency properties of two-dimensional Josephson junction arrays

A. B. Cawthorne, Paola Barbara, Christopher J. Lobb

Two-dimensional arrays of Josephson junctions have been shown to operate in a state in which the microwave oscillations of the junctions are phase-coherent. However, the performance of an array is strongly dependent on both the details of the load-coupling circuit and the characteristic parameters of the junctions. We have measured two-dimensional arrays of resistively shunted Josephson tunnel junctions which are capacitively coupled to a nearby detector junction. Changing the critical current of the junctions in our arrays, while keeping the junction parasitics and array coupling roughly the same, results in an unexpected change in device operation. We have also investigated variations of the coupling circuit. Numerical simulations of the detection circuit enable us to estimate the power output from the array and to optimize the parameters of the system.

IEEE Transactions on Applied Superconductivity•Jun 1, 1997•14 citations

Generation of coherent tunable Josephson radiation at microwave frequencies with narrowed linewidth

C. Varmazis, Robert D. Sandell, A. K. Jain +1 more

Coherent tunable microwave radiation (2–18 GHz) has been observed from two microbridge Josephson junctions coupled by a shunt resistor. The coherent power (∼4×10−12 W) is nearly four times the power emitted by a single junction. The linewidth of the radiation in the coherent state is one-half that from the individual microbridges.

Applied Physics Letters•Aug 15, 1978•41 citations

Observation of coherent microwave radiation emitted by coupled Josephson junctions

Thomas F. Finnegan, S. Wahlsten

We report here the results of a preliminary study of coherent microwave radiation emitted by a small array of interacting Josephson tunnel junctions, including the first direct observation of the superradiant state in pairs of junctions.

Applied Physics Letters•Dec 1, 1972•71 citations

Quantum Effects of Resistance-Shunted Josephson Junctions

Takeo Kato, Masatoshi Imada

Thermodynamics and transport properties of resistance-shunted Josephson junctions are studied theoretically in the tight-binding limit E C / E J ≪1, where E C and E J are a charging energy and a Josephson coupling energy respectively. Based on a phenomenological harmonic-oscillator model, weak coupling region K = R Q / R ≪1 is analytically studied, where R and R Q = h /(2 e ) 2 are a shunt resistance and the quantum resistance. In addition to an effective bandwidth \(2 \hbar \Delta_{\rm eff}\), we find that this multi-level system genuinely has a novel crossover at lower energy \(K \hbar \Delta_{\rm eff}\) below which the density of states becomes strongly degenerate. These two energy scales control the linear DC responses, optical responses, and nonlinear I - V characteristics. The lower energy crossover indicates the existence of a new class of strongly-correlated phenomena beyond the framework of the Kondo problem.

Journal of the Physical Society of Japan•Jan 1, 2000•4 citations
A model, based on the resistively shunted junction theory, is developed and used to study microwave absorption in weak-link Josephson junctions in high-Tc{T}_{c}Tc​ superconductors. Both linear and nonlinear cases of microwave absorption in Josephson junctions are analyzed. A comparison of the model with microwave absorption loop theory is presented along with a general condition for the applicability of both models. The nonlinear case was solved numerically and the threshold points of sharp microwave absorption are presented. At these points, a $2\ensuremath{\pi}$ phase quantization takes place within each microwave cycle, leading to an onset of a sharp rise of absorption. Existence of the $2\ensuremath{\pi}$ dynamic quantization is the key to the interpretation of nonlinear microwave absorption data. The nonlinear microwave absorption model is extended to the study of nonuniformly coupled junctions, and a general statement for the applicability of such a model is presented.
Calibrated measurements of both the real and imaginary parts of the microwave impedance of proximity coupled superconducting weak links have been made. The measurements were compared with analytic calculations based on several different models for the supercurrent Is and quasiparticle current. For dc bias currents I1 less than the critical current Ic, the experimental results are consistent with the Josephson relation Is=Ic sinφ, where φ is the quantum phase angle. However, for I1≳Ic, the Fourier component of Is at the Josephson frequency is found to be significantly less (∼0.65±0.1) than would be predicted from Is=Ic sinφ, and consistent with Tinkham’s analysis of a phase slip process. The experimental results indicate that the phase-dependent part of the quasiparticle current, if it exists at all, is no more than 10% of the total quasiparticle current. These results do not necessarily contradict previous measurements made on true tunnel junctions because of the fundamental differences between the two types of devices.
Two-dimensional arrays of Josephson junctions have been shown to operate in a state in which the microwave oscillations of the junctions are phase-coherent. However, the performance of an array is strongly dependent on both the details of the load-coupling circuit and the characteristic parameters of the junctions. We have measured two-dimensional arrays of resistively shunted Josephson tunnel junctions which are capacitively coupled to a nearby detector junction. Changing the critical current of the junctions in our arrays, while keeping the junction parasitics and array coupling roughly the same, results in an unexpected change in device operation. We have also investigated variations of the coupling circuit. Numerical simulations of the detection circuit enable us to estimate the power output from the array and to optimize the parameters of the system.
Thermodynamics and transport properties of resistance-shunted Josephson junctions are studied theoretically in the tight-binding limit E C / E J ≪1, where E C and E J are a charging energy and a Josephson coupling energy respectively. Based on a phenomenological harmonic-oscillator model, weak coupling region K = R Q / R ≪1 is analytically studied, where R and R Q = h /(2 e ) 2 are a shunt resistance and the quantum resistance. In addition to an effective bandwidth 2ℏΔeff2 \hbar \Delta_{\rm eff}2ℏΔeff​, we find that this multi-level system genuinely has a novel crossover at lower energy KℏΔeffK \hbar \Delta_{\rm eff}KℏΔeff​ below which the density of states becomes strongly degenerate. These two energy scales control the linear DC responses, optical responses, and nonlinear I - V characteristics. The lower energy crossover indicates the existence of a new class of strongly-correlated phenomena beyond the framework of the Kondo problem.