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DY: Dynamik und Statistische Physik

DY 23: Brownsche Bewegung

DY 23.1: Vortrag

Dienstag, 12. März 2002, 11:45–12:00, H3

Resonant discrete breathers in Josephson ladders — •M. Schuster, P. Binder, and A.V. Ustinov — Physikalisches Institut III, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erwin-Rommel-Straße 1, 91058 Erlangen

Homogeneous nonlinear lattices can exhibit localized time-periodic solutions, so-called “discrete breathers” [1]. In lattices formed of rotors, breathers can also be manifested by a spatially confined ensemble of sites in the rotational state while the remaining lattice oscillates at a small amplitude. They persist in dissipative, yet homogeneously driven rotor lattices, making the latter interesting for experiments. We experimentally study the properties of rotobreathers in Josephson ladders, which consist of a one-dimensional network of Josephson junctions arranged along the spars and rungs of a ladder. Here a single junction behaves identically to an ideal underdamped rotor (a mathematical pendulum with small dissipation). In our work, we concentrate on the resonant interaction of the localized breather states with spatially extended linear electromagnetic excitations of the junction lattice. We observe resonant steps on experimental current-voltage characteristics, which are reproduced in numerical simulations and explained by an analytical model [2].

[1] S. Flach and C. R. Willis, Physics Reports 295, 181 (1998).

[2] M. Schuster et al., to appear in Phys. Rev. E 85 (2002).