title: Localization of bosonic atoms by fermionic impurities in a three-dimensional optical lattice.
abstract: We observe a localized phase of ultracold bosonic quantum gases in a 3-dimensional optical lattice induced by a small contribution of fermionic atoms acting as impurities in a Fermi-Bose quantum gas mixture. In particular, we study the dependence of this transition on the fermionic (40)K impurity concentration by a comparison to the corresponding superfluid to Mott-insulator transition in a pure bosonic (87)Rb gas and find a significant shift in the transition parameter. The observed shift is larger than expected based on a simple mean-field argument, which indicates that disorder-related effects play a significant role.
authors.affiliation: Institut für Laserphysik, Luruper Chaussee 149, 22761 Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Ospelkaus
authors.forename: C
authors.initials: C
authors.lastname: Ospelkaus
authors.forename: O
authors.initials: O
authors.lastname: Wille
authors.forename: M
authors.initials: M
authors.lastname: Succo
authors.forename: P
authors.initials: P
authors.lastname: Ernst
authors.forename: K
authors.initials: K
authors.lastname: Sengstock
authors.forename: K
authors.initials: K
authors.lastname: Bongs