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Q: Fachverband Quantenoptik und Photonik

Q 11: Quantengase: Bosonen im Gitter II

Q 11.2: Talk

Monday, March 2, 2009, 16:45–17:00, VMP 6 HS-A

RPA Studies of Dynamic Response of Ultracold Bose Gases in 1D Optical Lattices — •Markus Hild, Panagiota Papakonstantinou, Felix Schmitt, and Robert Roth — Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt

We study the dynamic response of ultracold Bose gases in one-dimensional optical lattices based on the Bose-Hubbard model (BHM) using a generalized random-phase approximation. Our aim is to simulate Bragg-spectroscopy experiments using modulated optical lattice potentials to probe the system [PRL 92 (2004) 130403, PRL 98 (2007) 130404]. We compare the response function obtained at different levels of the RPA scheme with results from a linear response analysis based on the full eigenspectrum of the BHM. The evolution of the response as a function of interaction strength and lattice size is investigated. The results are in very good agreement with experiments and due to the minimal numerical effort RPA emerges as a powerfull tool to gain insights on the dynamics of bosonic lattice systems at experimentally relevant system sizes.