Interactions between Josephson vortices and breathers

Abstract

We study vortex-breather collisions in a Josephson-junction ladder array. We have computed parameters values of the system for which both types of structures coexist in the ladder. In order of increasing bias current, we have found different possible scenarios for vortex-breather collisions. (i) At low bias current, the breather acts as a pinning center for a single vortex. (ii) Increasing the current, the vortex excites multisite breathers in its wake and is finally pinned by the breather. (iii) At still higher current, a whirling mode front is excited by the vortex. However, the breather still acts as a pinning center, but now for the front. (iv) At higher values of the bias, the front is able to destroy the breather. For scenario (i), we have also studied thermal activation properties associated with the presence of the vortex-breather pair in the array.