Thermal depinning of fluxons in discrete Josephson rings

Experimental Observation of Fluxon Diffusion in Josephson Rings

We present switching current measurements in niobium-aluminum oxideniobium underdamped Josephson rings. Underdamped Josephson rings display hysteretic current-voltage curves which can be characterized by their switching current, the value of applied current at which the junctions switch to the energy-gap voltage. The value of the switching current is strongly affected by temperature and by the ...

Influence of thermal fluctuations on Cherenkov radiation from fluxons in dissipative Josephson systems

Engineering double-well potentials with variable-width annular Josephson tunnel junctions.

Long Josephson tunnel junctions are non-linear transmission lines that allow propagation of current vortices (fluxons) and electromagnetic waves and are used in various applications within superconductive electronics. Recently, the Josephson vortex has been proposed as a new superconducting qubit. We describe a simple method to create a double-well potential for an individual fluxon trapped in ...

Dynamics of an underdamped Josephson-junction ladder.

We show analytically that the dynamical equations for an underdamped ladder of coupled small Josephson junctions can be approximately reduced to the discrete sine-Gordon equation. As numerical confirmation, we solve the coupled Josephson equations for such a ladder in a magnetic field. We obtain discrete-sine-Gordon-like IV characteristics, including a flux flow and a “whirling” regime at low a...

Fluxon motion in one-dimensional Josephson junction arrays

Current-voltage ( I V ) characteristics of linear and annular discrete arrays of underdamped small Josephson junctions with different values of single loop inductances are calculated numerically and compared with those obtained for continuum long Josephson junctions. The resonances between the moving fluxon and the linear waves caused by the array discreteness induce steps on t h e / V c u r v ...