Solitons and Long Josephson Junctions

TL;DR

This paper discusses the behavior of magnetic flux quanta in long Josephson junctions modeled by a perturbed sine-Gordon equation, highlighting their physical phenomena and potential applications in superconductive circuits.

Contribution

It provides a detailed analysis of fluxon dynamics in long Josephson junctions using the sine-Gordon model and explores their applications in superconductive devices.

Findings

Fluxons behave as solitons in long Josephson junctions.

Current-voltage characteristics show step structures due to fluxon dynamics.

Fluxon-based devices can serve as oscillators and amplifiers.

Abstract

Magnetic flux quanta, of value h/2e, in long Josephson junctions behave as (quasi) solitons. Fluxon dynamical states are well described by a perturbed sine-Gordon equation model, with boundary conditions determined by the junction geometry and by externally applied magnetic fields, and they give rise to readily measurable physical phenomena, such as step structure in current-voltage characteristics and microwave radiation emission. Devices based on fluxon propagation offer potentially interesting applications as oscillators and amplifiers - as well as digital applica- tions, described elsewhere in this volume - in high performance integrated superconductive circuits.