We have produced a quantum degenerate mixture of fermionic alkali-metal 6 Li and bosonic spin-singlet 174 Yb gases. This was achieved using sympathetic cooling of lithium atoms by evaporatively cooled ytterbium atoms in a far-off-resonant optical dipole trap. We observe the coexistence of Bose-condensed (T /T c 0.8) 174 Yb with 2.3 × 10 4 atoms and Fermi degenerate (T /T F 0.3) 6 Li with 1.2 × 10 4 atoms. Quasipure Bose-Einstein condensates of up to 3 × 10 4 174 Yb atoms can be produced in single-species experiments. Our results mark a significant step toward studies of few-and many-body physics with mixtures of alkali-metal and alkaline-earthmetal-like atoms, and for the production of paramagnetic polar molecules in the quantum regime. Our methods also establish a convenient scheme for producing quantum degenerate ytterbium atoms in a 1064 nm optical dipole trap.

We report on the realization of a stable mixture of ultracold lithium and ytterbium atoms confined in a far-off-resonance optical dipole trap. We observe sympathetic cooling of 6Li by 174Yb and extract the s-wave scattering length magnitude |a(6Li-174Yb)|=(13±3)a0 from the rate of interspecies thermalization. Using forced evaporative cooling of 174Yb, we achieve reduction of the 6Li temperature to below the Fermi temperature, purely through interspecies sympathetic cooling.

We report on the realization of an ultracold mixture of lithium atoms in the ground state and ytterbium atoms in an excited metastable ( 3 P2) state. Such a mixture can support broad magnetic Feshbach resonances which may be utilized for the production of ultracold molecules with an electronic spin degree of freedom, as well as novel Efimov trimers. We investigate the interaction properties of the mixture in the presence of an external magnetic field and find an upper limit for the background interspecies two-body inelastic decay coefficient of K ′ 2 < 3 × 10 −12 cm 3 /s for the 3 P2 mJ = −1 substate. We calculate the dynamic polarizabilities of the Yb( 3 P2) magnetic substates for a range of wavelengths, and find good agreement with our measurements at 1064 nm. Our calculations also allow the identification of magic frequencies where Yb ground and metastable states are identically trapped and the determination of the interspecies van der Waals coefficients.Ultracold elemental mixtures provide unique opportunities to study few-and many-body physics with mass-mismatched atomic partners [1] and diatomic polar molecules [2, 3]. While the bulk of elemental mixture experiments have been performed using ground-state bialkali systems, the recent production of ground state mixtures of alkali and alkaline-earth-like atoms [4][5][6][7] further extend the experimental possibilities. These include powerful quantum simulation and information protocols [8] and tests of fundamental symmetries [9] with paramagnetic polar molecules. While tunable two-body interactions that are important for these advances have been proposed in such mixtures [10], they have not yet been experimentally detected.In this Letter we report the realization a new class of heteronuclear mixtures in which one atomic component is in an electronically excited state, using lithium ( 6 Li) and ytterbium ( 174 Yb) atoms. This establishes a highly mass-mismatched atomic mixture where tunable anisotropic interactions are expected to play a strong role [11], laying a foundation for future studies of ultracold trapped paramagnetic polar molecules and Efimov trimers with very large mass imbalance [12]. We measure inelastic interactions in the mixture and observe the relative suppression of interspecies inelastic processes. Our experimental methods also demonstrate new techniques of production and manipulation of spin components in the metastable 3 P 2 state of Yb.The study and control of anisotropic interactions is an increasingly important topic in ultracold atomic systems. In addition to their impact on many-body physics [3,8,13], anisotropic two-body interactions are proving to be of great interest for generating magnetically tunable interactions, as has been calculated theoretically [14] and observed experimentally in a mixture of ground and excited state Yb atoms [15]. The latter result applied in the context of the Li+Yb combination points to an alternative route towards tunable interactions, where the ground

Quantum-degenerate mixtures of one-electron and two-electron atoms form the starting point for studying few-and many-body physics of mass-imbalanced pairs as well as the production of paramagnetic polar molecules. We recently reported the achievement of dual-species quantum degeneracy of a mixture of lithium and ytterbium atoms. Here we present details of the key experimental steps for the all-optical preparation of these mixtures. Further, we demonstrate the use of the magnetic field gradient tool to compensate for the differential gravitational sag of the two species and control their spatial overlap.

2,2,2-Trifluoroethanol (TFE)-water is a convenient solvent for the precise conductometric measurement of solvolysis rates. A comparison of results in TFE-water with those in ethanol-water gives a useful indication of the role of changing nucleophilicity in solvolysis reactions. It has been found that the a-and /3-deuterium effects in 1-phenylethyl chloride, which in ethanol-water are at or near a maximum characteristic of a limiting reaction, are not much changed in TFE-water. However, for /-butyl-d» chloride the isotope effects are larger in TFE solutions than in ethanol-water. This is explained on the basis of the incursion of some rate-determining elimina-