Heidelberg 2015 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 15: Poster: Quantum Optics and Photonics I
Q 15.2: Poster
Montag, 23. März 2015, 17:00–19:00, C/Foyer
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 (SF) state to the Mott insulator (MI) is clearly displayed in the decay of the inelastic scattering cross-section for increasing onsite interaction U/J .
To understand the role of interactions in this process, we obtain analytical expressions for the cross-section from a Bogoliubov expansion, valid in the regime of small condensate depletion, and from a strong-coupling expansion, valid in the regime of large interactions U/J. This allows for the description of the inelastic cross-section’s decay in the entire range of the relevant system parameters, excluding the vicinity of the critical point of the MI-SF phase transition.
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 . In the strong-interaction regime, the decay is quadratic and vanishes only as U/J→∞, resulting in a non-vanishing inelastic cross section throughout the entire Mott phase. To support our analytical results, we present numerical studies obtained from exact diagonalization methods.
 S. Sanders, F. Mintert, E. Heller, PRL 105, 035301 (2010)
K. Mayer, A. Rodriguez, A. Buchleitner, PRA 90, 023629 (2014)