title: Precision measurements on a tunable Mott insulator of ultracold atoms.
abstract: We perform precision measurements on a Mott-insulator quantum state of ultracold atoms with tunable interactions. We probe the dependence of the superfluid-to-Mott-insulator transition on the interaction strength and explore the limits of the standard Bose-Hubbard model description. By tuning the on-site interaction energies to values comparable to the interband separation, we are able to quantitatively measure number-dependent shifts in the excitation spectrum caused by effective multibody interactions.
authors: Institut für Experimentalphysik and Zentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria.
authors: M J
authors: MJ
authors: Mark
authors: E
authors: E
authors: Haller
authors: K
authors: K
authors: Lauber
authors: J G
authors: JG
authors: Danzl
authors: A J
authors: AJ
authors: Daley
authors: H-C
authors: HC
authors: Nägerl