Berlin 2014 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 49: Quantum gases: Lattices I

Q 49.3: Vortrag

Donnerstag, 20. März 2014, 17:00–17:15, UDL HS2002

Matter-wave scattering from interacting ultracold bosons in optical lattices — •Klaus Mayer, Alberto Rodriguez, and Andreas Buchleitner — Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg

We study matter-wave scattering from 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 around the condensate and obtain an analytical expression for the cross-section, valid in the regime of small condensate depletion. This allows for the description of the inelastic cross-section’s decay in a large range of the relevant system parameters. In the weak-interaction regime, the cross section is found to decay linearly, with a slope that is independent of the bosonic density and the system size. To support our analytical results, we present numerical studies obtained from exact diagonalization methods.

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