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Q: Quantenoptik und Photonik
Q 44: Gruppenberichte Quantengase
Q 44.4: Gruppenbericht
Donnerstag, 25. März 2004, 18:00–18:30, HS 225
Low dimensional Bose gases in optical lattices — •Michael Köhl, Thilo Stöferle, Henning Moritz, Christian Schori, and Tilman Esslinger — Institut für Quantenelektronik, ETH Zürich, CH-8093 Zürich
We report on the realization and investigation of one-dimensional trapped Bose gases in the mean-field and in the strongly interacting regime. In the weakly interacting mean-field regime we have characterized the gas by measuring collective excitations and we find the ratio of the frequencies of the lowest compressional (breathing) mode and the dipole mode to be (ωB/ωD)2≃3.1. For a thermal gas we measure (ωB/ωD)2≃4 [1]. By adding a periodic potential along the axis of the 1D gas we can tune the gas from a strongly interacting superfluid into the Mott-insulating phase. We study the gas by Bragg spectroscopy and find that the excitation spectra cannot be understood by Bogoliubov theory [2]. The excitation spectra of both phases are compared to the three-dimensional gas and to the crossover regime from one to three dimensions. The coherence properties of the gas in all configurations are measured quantitatively.
[1] H. Moritz et al., to appear in Phys. Rev. Lett.
[2] T. Stöferle et al., preprint 2003.