Spontaneous creation of discrete breathers in Josephson arrays

TL;DR

This paper demonstrates the experimental creation of discrete breather states in Josephson arrays, showing how uniform external currents induce localized modes during the transition from static to dynamic states.

Contribution

It provides the first experimental evidence of discrete breathers in Josephson arrays and explains their formation through vortex penetration.

Findings

Discrete breathers are generated during the transition to dynamic states.

Resonant states evolve into localized breather states under uniform current.

Breather formation is linked to vortex penetration into the system.

Abstract

We report on the experimental generation of discrete breather states (intrinsic localized modes) in frustrated Josephson arrays. Our experiments indicate the formation of discrete breathers during the transition from the static to the dynamic (whirling) system state, induced by a uniform external current. Moreover, spatially extended resonant states, driven by a uniform current, are observed to evolve into localized breather states. Experiments were performed on single Josephson plaquettes as well as open-ended Josephson ladders with 10 and 20 cells. We interpret the breather formation as the result of the penetration of vortices into the system.