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P: Fachverband Plasmaphysik

P 18: Poster: Theorie/Modellierung

P 18.2: Poster

Wednesday, April 1, 2009, 17:30–19:30, Foyer des IfP

Berezinskii-Kosterlitz-Thouless transition in two-dimensional dipole systems — •Alexey Filinov¹, Nikolay Prokof’ev², and Michael Bonitz¹ — ¹Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstr. 15, D-24098 Kiel, Germany — ²Department of Physics, University of Massacusetts, Amherst, Massachusetts 01003, USA

Dilute dipole gases of polar molecules and indirect excitons in quantum wells are of increasing interest in recent experimental realizations [1], since they allow to realize and control correlation and quantum degeneracy effects. Using path integral Monte Carlo we investigate the normal-superfluid transition in a system of 2D bosonic dipoles which models such experiments in the full temperature-density plane. The critical temperature, superfluid fraction, thermodynamic sound speed and compressibility have been evaluated for different dipole coupling strengths/densities. For indirect excitons at high densities the dipole approximation becomes invalid. We, therefore, take into account the internal exciton structure and derive new effective interaction which crucially effects the phase diagram at high densities.

[1] J.M. Sage at al., Phys. Rev. 94, 203001 (2005); D. Wang at al., Phys. Rev. 93, 243005 (2004). [2] Timofeev V et al 2007 J. Phys: Cond. Matt. 19 295209.