New fluxon resonant mechanism in annular Josephson tunnel structures.
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.
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Istituto di Cibernetica E. Caianiello del CNR, I-80078 Pozzuoli, Italy.
Lisitskiy
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MP
Rotoli
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G
Cristiano
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R
Barone
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A