Dynamic properties of Josephson-junction circuits

Marian Darula, P. Seidel, F Busses +1 more

We have studied via computer simulations the dynamical properties of a circuit consisting of two arrays of Josephson junctions closed into a superconducting loop. Due to an internal circuit resonance the phase locking of Josephson junctions is enhanced, which makes possible the application of such a circuit as a source of coherent microwave radiation. The optimal circuit parameters and the influence of thermal noise are discussed. It is shown that the critical spread in junction parameters is about twice that of linear Josephson junction arrays. The possibility of tuning such a device is demonstrated.

N. F. Pedersen

I. N. Askerzade, Ali Bozbey, Mehmet Cantürk

Hassan Pahlavani

A quantum mesoscopic electrical LC-circuit with charge discreteness including a Josephson junction is considered and a nonlinear Hamiltonian that describing the dynamic of such circuit is introduced. The quantum dynamical behavior (persistent current probability) is studied in the charge and phase regimes by numerical solution approaches. The time evolution of charge and current, number-difference and the bosonic phase and also the energy spectrum of a quantum mesoscopic electric LC-circuit with charge discreteness that coupled with a Josephson junction device are investigated. We show the role of the coupling energy and the electrostatic Coulomb energy of the Josephson junction in description of the quantum behavior and the spectral properties of a quantum mesoscopic electrical LC-circuits with charge discreteness.

Thilo Bauch, Edoardo Trabaldo, Floriana Lombardi

Serhii E. Shafranjuk, John B. Ketterson

The switching dynamics of a double-barrier Josephson junction is analyzed as a function of the microscopic properties of its electrodes. In particular, it is found that the nonstationary behavior of the Josephson phase difference is very sensitive to dissipation mechanisms acting inside the intrinsic shunt. The leading factor that determines the dissipation is the local electron density of states N(E) inside the electrodes. The roles of junction geometry, electrode purity, and interface quality are discussed and how they affect the details of N(E), hence the resulting phase dynamics. The microscopic analyses allow optimization of the performance of double-barrier Josephson junction-based rapid-single-flux-quantum circuits in two ways: 1) decreasing the switching time of Josephson elements and 2) reducing the excess wiring. Such an analysis is facilitated with the aid of a lumped circuit representation which generalizes the nonlinear resistive-shunted-junction model.