title: Preparation and spectroscopy of a metastable Mott-insulator state with attractive interactions.
abstract: We prepare and study a metastable attractive Mott-insulator state formed with bosonic atoms in a three-dimensional optical lattice. Starting from a Mott insulator with Cs atoms at weak repulsive interactions, we use a magnetic Feshbach resonance to tune the interactions to large attractive values and produce a metastable state pinned by attractive interactions with a lifetime on the order of 10 s. We probe the (de)excitation spectrum via lattice modulation spectroscopy, measuring the interaction dependence of two- and three-body bound-state energies. As a result of increased on-site three-body loss we observe resonance broadening and suppression of tunneling processes that produce three-body occupation.
authors.affiliation: Institut für Experimentalphysik und Zentrum für Quantenphysik, Universität Innsbruck, 6020 Innsbruck, Austria.
authors.forename: M J
authors.initials: MJ
authors.lastname: Mark
authors.forename: E
authors.initials: E
authors.lastname: Haller
authors.forename: K
authors.initials: K
authors.lastname: Lauber
authors.forename: J G
authors.initials: JG
authors.lastname: Danzl
authors.forename: A
authors.initials: A
authors.lastname: Janisch
authors.forename: H P
authors.initials: HP
authors.lastname: Büchler
authors.forename: A J
authors.initials: AJ
authors.lastname: Daley
authors.forename: H-C
authors.initials: HC
authors.lastname: Nägerl