title: New fluxon resonant mechanism in annular Josephson tunnel structures.
abstract: A novel dynamical state has been observed in the dynamics of a perturbed 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. In 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. This occurs because the size of nonlinear excitations is comparable with that of the system.
authors.affiliation: Istituto di Cibernetica E. Caianiello del CNR, I-80078 Pozzuoli, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Nappi
authors.forename: M P
authors.initials: MP
authors.lastname: Lisitskiy
authors.forename: G
authors.initials: G
authors.lastname: Rotoli
authors.forename: R
authors.initials: R
authors.lastname: Cristiano
authors.forename: A
authors.initials: A
authors.lastname: Barone