Hannover 2013 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 56: Poster III

Q 56.24: Poster

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

Matter-wave scattering from interacting ultracold bosons in optical lattices — •Klaus Mayer, Alberto Rodriguez, and Andreas Buchleitner — Institut f. Physik, Universität Freiburg, Germany

We study matter-wave scattering from a system of ultracold bosons in a one-dimensional optical lattice, described by a Bose-Hubbard Hamiltonian. The phase transition from the superfluid state to the Mott Insulator is clearly displayed in the decay of the inelastic component of the scattering cross-section for increasing onsite interaction U [1]. In order to understand the role of interactions in this process, we perform a Bogoliubov expansion for small U and obtain an analytical expression for the cross-section in the weakly-interacting regime. We identify the different contributions to the inelastic scattering signal in terms of one- and two-quasiparticle excitations above the condensate in the superfluid phase. To support the analytical description, we present numerical results obtained from exact diagonalization methods.

[1] S. Sanders, F. Mintert, E. Heller, Phys. Rev. Lett. 105, 035301 (2010)