We report on controlled doping of an ultracold Rb gas with single neutral Cs impurity atoms. Elastic two-body collisions lead to a rapid thermalization of the impurity inside the Rb gas, representing the first realization of an ultracold gas doped with a precisely known number of impurity atoms interacting via s-wave collisions. Inelastic interactions are restricted to a single three-body recombination channel in a highly controlled and pure setting, which allows us to determine the Rb-Rb-Cs three-body loss rate with unprecedented precision. Our results pave the way for a coherently interacting hybrid system of individually controllable impurities in a quantum many-body system.We report on controlled doping of an ultracold Rb gas with single neutral Cs impurity atoms. Elastic two-body collisions lead to a rapid thermalization of the impurity inside the Rb gas, representing the first realization of an ultracold gas doped with a precisely known number of impurity atoms interacting via s-wave collisions. Inelastic interactions are restricted to a single three-body recombination channel in a highly controlled and pure setting, which allows us to determine the Rb-Rb-Cs three-body loss rate with unprecedented precision. Our results pave the way for a coherently interacting hybrid system of individually controllable impurities in a quantum many-body system.

arXiv:1204.6051Physical Review LettersDec 4, 2012199 citations

Interspecies interaction in a strongly imbalanced Bose-Bose mixture

Shincy John, Nicolas Spethmann, Claudia Weber +3 more

In our experiment, we study and intend to manipulate the interaction between the two species viz. rubidium (Rb) and caesium (Cs) at ultracold temperatures. We propose to explore the world of many body physics and small particle physics by inserting a few Cs atoms into a Rb condensate. Our experimental set up consists of a double MOT system, with a magnetic trap in the QUIC configuration. The Rb atoms are cooled evaporatively using a species selective microwave frequency such that Cs remains unaffected due to a 2.4 Ghz difference in their hyperfine transitions, producing a Rb condensate with around 105 atoms.In our experiment, we study and intend to manipulate the interaction between the two species viz. rubidium (Rb) and caesium (Cs) at ultracold temperatures. We propose to explore the world of many body physics and small particle physics by inserting a few Cs atoms into a Rb condensate. Our experimental set up consists of a double MOT system, with a magnetic trap in the QUIC configuration. The Rb atoms are cooled evaporatively using a species selective microwave frequency such that Cs remains unaffected due to a 2.4 Ghz difference in their hyperfine transitions, producing a Rb condensate with around 105 atoms.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)Jun 1, 20090 citations

Trapping and interactions of an ultracold gas of Cs $_{2}$ moleculesTrapping and interactions of an ultracold gas of Cs$_{2}$ molecules

Tobias Kraemer, Manfred J. Mark, P. Waldburger +4 more

Bulletin of the American Physical SocietyMay 20, 20050 citations

Quantum Engineering of a Low-Entropy Gas of Heteronuclear Bosonic Molecules in an Optical Lattice

Lukas Reichsöllner, Andreas Schindewolf, T. Takekoshi +2 more

We demonstrate a generally applicable technique for mixing two-species quantum degenerate bosonic samples in the presence of an optical lattice, and we employ it to produce low-entropy samples of ultracold ^{87}Rb^{133}Cs Feshbach molecules with a lattice filling fraction exceeding 30%. Starting from two spatially separated Bose-Einstein condensates of Rb and Cs atoms, Rb-Cs atom pairs are efficiently produced by using the superfluid-to-Mott insulator quantum phase transition twice, first for the Cs sample, then for the Rb sample, after nulling the Rb-Cs interaction at a Feshbach resonance's zero crossing. We form molecules out of atom pairs and characterize the mixing process in terms of sample overlap and mixing speed. The dense and ultracold sample of more than 5000 RbCs molecules is an ideal starting point for experiments in the context of quantum many-body physics with long-range dipolar interactions.We demonstrate a generally applicable technique for mixing two-species quantum degenerate bosonic samples in the presence of an optical lattice, and we employ it to produce low-entropy samples of ultracold ^{87}Rb^{133}Cs Feshbach molecules with a lattice filling fraction exceeding 30%. Starting from two spatially separated Bose-Einstein condensates of Rb and Cs atoms, Rb-Cs atom pairs are efficiently produced by using the superfluid-to-Mott insulator quantum phase transition twice, first for the Cs sample, then for the Rb sample, after nulling the Rb-Cs interaction at a Feshbach resonance's zero crossing. We form molecules out of atom pairs and characterize the mixing process in terms of sample overlap and mixing speed. The dense and ultracold sample of more than 5000 RbCs molecules is an ideal starting point for experiments in the context of quantum many-body physics with long-range dipolar interactions.

arXiv:1607.06536Physical Review LettersFeb 17, 201782 citations

Trapping and interactions of an ultracold gas of Cs

_{2}

molecules