Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 10: Superconductivity - Tunneling, Josephson Junctions, SQUIDs

TT 10.2: Vortrag

Samstag, 5. März 2005, 08:45–09:00, TU H104

Experimental observation of moving 4π−kinks in Josephson-junction arrays — •Judith Pfeiffer, Marcus Schuster, Abdufarrukh A. Abdumalikov, and Alexey V. Ustinov — Physikalisches Institut III, Universität Erlangen-Nürnberg, 91058 Erlangen

We experimentally study the dynamics of kinks (magnetic vortices) in annular parallel arrays of underdamped Josephson junctions with different discreteness. Parallel arrays of Josephson junctions are described by the discrete sine-Gordon-model. For small discreteness parameters, we measured very precise phase locking resonances. For systems with higher discreteness, we observe bunched states of two moving kinks, which form either a 4π−kink or various bound states of two phase locked 2π−kinks with finite distance between them. To our knowledge, this is the first experimental observation of dynamically stable 4π−kinks, which have been predicted for discrete sine-Gordon systems by Peyrard and Kruskal [1]. Our numerical results agree quantitativly with the experimental data.

[1] M. Peyrard, M. D. Kruskal Phys. Ref. D 14 (1984), 88