Regensburg 2004 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 31: Supraleitung: Vortexdynamik, Vortexphasen, Pinning
TT 31.9: Vortrag
Freitag, 12. März 2004, 12:15–12:30, H20
Competitive localization of vortex lines or interacting bosons by a defect — •Jan Kierfeld1 and Valerii Vinokur2 — 1MPI für Kolloid- und Grenzflächenforschung, 14424 Potsdam — 2Materials Science Division, Argonne National Laboratory
We present a theory describing the localization of N three-dimensional vortex lines or two-dimensional bosons with short-ranged repulsive interaction which are competing for a single columnar defect or potential well. For N=2 we use a necklace model formulation to find a delocalization transition between two different states with a single bound particle. The transition is characterized by the onset of particle exchange on the defect. For strong repulsive interaction between vortex lines a permutation symmetry is broken and the potential well is occupied by the same particle at all times. For decreasing repulsion or increasing temperature a transition into a different bound state takes place in which the particles occupy the potential well alternately. A generalization of this transition to arbitrary vortex number N is proposed.