Regensburg 2007 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 11: Superfluidity and Bose-Einstein condensation

DY 11.2: Talk

Tuesday, March 27, 2007, 10:00–10:15, H2

Transport of Bose-Einstein condensates beyond the Gross-Pitaevskii approach — •Thomas Ernst¹, Michael Hartung¹, Tobias Paul², and Peter Schlagheck¹ — ¹Institut für Theoretische Physik, Universität Regensburg — ²Laboratoire de Physique Théorique et Modèles Statistiques, Université Paris Sud, Orsay

We study the transport of Bose-Einstein condensates through scattering potentials in quasi one-dimensional waveguides. While previous works used the Gross-Pitaevskii equation to calculate this process, we employ an approach which goes beyond this mean field theory and which is able to take into account excitations of the condensate as well as its depletion rate. This approach is based on a cumulant expansion [1], where we use a truncation scheme that is formally valid for weak interactions and a large number of atoms. We apply it to the scattering problem of a propagating BEC on a double barrier potential, where resonant transmission of the condensate takes place via the population of dynamically unstable scattering states. Our results confirm the validity of previous calculations of these processes based on the Gross-Pitaevskii equation [2].
T. Köhler and K. Burnett, Phys. Rev. A 65, 033601 (2002)
T. Paul, K. Richter and P. Schlagheck, Phys. Rev. Lett. 94, 020404 (2005)