Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 30: Matter At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 1
TT 30.10: Vortrag
Mittwoch, 28. März 2012, 18:00–18:15, H 3005
Dislocation-induced superfluidity in a model supersolid — •Debajit Goswami1, Kinjal Dasbiswas2, Chi-Deuk Yoo3, and Alan Dorsey2 — 1Universität des Saarlandes, Saarbrücken, Germany — 2University of Florida, Gainesville, USA — 3University of Minnesota, Minneapolis, USA
Motivated by recent experiments on the supersolid behavior of 4He, we study the effect of an edge dislocation in promoting superfluidity in a Bose crystal. Using Landau theory, we couple the elastic strain field of the dislocation to the superfluid density, and use a linear analysis to show that superfluidity nucleates on the dislocation before occurring in the bulk of the solid. Moving beyond the linear analysis, we develop a systematic perturbation theory in the weakly nonlinear regime, and use this method to integrate out transverse degrees of freedom and derive a one-dimensional Landau equation for the superfluid order parameter. We then extend our analysis to a network of dislocation lines, and derive an XY model for the dislocation network by integrating over fluctuations in the order parameter. Our results show that the ordering temperature for the network has a sensitive dependence on the dislocation density, consistent with numerous experiments that find a clear connection between the sample quality and the supersolid response.