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

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 ...

Fluxon dynamics in long annular Josephson tunnel junctions

Scaling Laws for Fluxon Formation in Annular Josephson Tunnel Junctions

Although equilibrium, or adiabatic, correlation lengths ξ ad (T) diverge at the critical temperature T c of continuous phase transitions, correlation lengths always remain bounded, in practice. This is because causality prevents a system becoming ordered on very large scales within the finite time in which transitions are implemented. In consequence, the order parameter fields become frustrated...

Spontaneous fluxon formation in annular Josephson tunnel junctions

Superelliptic Josephson Tunnel Junctions

The most important practical characteristic of a Josephson junction is its critical current. The shape of the junction determines the specific form of the magnetic-field dependence of the its Josephson current. Here we address the magnetic diffraction patterns of specially shaped planar Josephson tunnel junctions. We focus on a wide ensemble of generalized ellipses, called superellipses, which ...