Observation of a New Fluxon Resonant Mechanism in Annular Josephson Tunnel Structures

TL;DR

This paper reports the discovery of a new fluxon resonant mechanism in annular Josephson tunnel structures, characterized by a unique dynamical state observed as a singularity in the current-voltage characteristic, involving rotating fluxon pairs.

Contribution

It introduces a novel fluxon resonance mechanism distinct from known Fiske and zero-field steps, supported by experimental observation and numerical simulations.

Findings

Identified a new resonant state in Josephson junctions

Demonstrated fluxon pair rotation as a key dynamic feature

Observed singularities in current-voltage characteristics

Abstract

A novel dynamical state has been observed in the dynamics of a perdurbed sine-Gordon system. This resonant state, has been experimentally observed as a singularity in the dc current voltage characteristic of an annular Josephson tunnel junction, excited in the presence of a magnetic field. With this respect, it can be assimilated to self-resonances known as Fiske steps. Differently from these, however, we demonstrate, on the basis of numerical simulations, that its detailed dynamics involves rotating fluxon pairs, a mechanism associated, so far, to self-resonances known as zero-field steps.