Hannover 2013 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 56: Poster III

Q 56.10: Poster

Donnerstag, 21. März 2013, 16:00–18:30, Empore Lichthof

Bogoliubov modes at the edge of a BEC — Aboulaye Diallo and •Carsten Henkel — Institute of Physics and Astronomy, Universität Potsdam

The quantum field theory of Bose-Einstein condensed gases can be efficiently built from the solutions to the Bogoliubov-de Gennes (BdG) equations. Indeed, they provide the quantum depletion of the condensate at zero temperature, the density of thermally excited particles, and higher correlation properties like the anomalous average. We study BdG solutions at the edge of a condensate, as a generalization of the wave mechanics in a linear potential. The condensate is described by a generalized Airy function (second Painlevé transcendant) that connects smoothly to the Thomas-Fermi profile [1]. The BdG equations are solved numerically and compared to the local density approximation. We apply symplectic techniques from Hamiltonian mechanics to enforce physical (stable) solutions. The scattering phase of the BdG modes helps to clarify the role of the potential well near the condensate boundary that appears in the Hartree-Fock approximation.

[1] F. Dalfovo, L. Pitaevskii, and S. Stringari, Phys. Rev. A 54 (1996) 4213; D. Margetis, Phys. Rev. A 61 (2000) 055601.