We investigate the momentum-dependent transport of 1D quasicondensates in quasiperiodic optical lattices. We observe a sharp crossover from a weakly dissipative regime to a strongly unstable one at a disorder-dependent critical momentum. In the limit of nondisordered lattices the observations suggest a contribution of quantum phase slips to the dissipation. We identify a set of critical disorder and interaction strengths for which such critical momentum vanishes, separating a fluid regime from an insulating one. We relate our observation to the predicted zero-temperature superfluid-Bose glass transition.

We discuss the implementation and characterization of the source of a slow, intense, and collimated beam of rubidium atoms. The cold atomic beam is produced by two-dimensional magneto-optical trapping in directions transverse to the atomic beam axis and unbalanced Doppler cooling in the axial direction. The vacuum design allows use of relatively low laser power and a considerably simplified assembly. The atomic beam has a high flux of about 2 ϫ 10 10 atoms/ s at a total cooling laser power of 55 mW. It has a narrow longitudinal velocity distribution with mean velocity 15 m / s with full width at half maximum 3.5 m / s and has a low divergence of 26 mrad. The high flux enables ultrafast loading of about 10 10 atoms into a three-dimensional ͑3D͒ magnetooptical trap within 500 ms. The variation of the atomic beam flux was studied as a function of the rubidium vapor pressure, cooling laser power, transverse cooling laser beam length, detuning of the cooling laser, and relative intensities of the cooling beams along the atomic beam axis. We also discuss a detailed comparison of our measurements of the cold atomic beam with a 3D numerical simulation.

We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6 Li and 40 K atoms with large atom numbers. The MOT simultaneously contains 5.2 × 10 9 6 Li-atoms and 8.0 × 10 9 40 K-atoms, which are continuously loaded by a Zeeman slower for 6 Li and a 2D-MOT for 40 K. The atom sources induce capture rates of 1.2 × 10 9 6 Li-atoms/s and 1.4 × 10 9 40 K-atoms/s. Trap losses due to light-induced interspecies collisions of ∼65% were observed and could be minimized to ∼10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture.

We investigate the formation of weakly bound, electronically excited, heteronuclear 6 Li 40 K * molecules by single-photon photoassociation in a magneto-optical trap. We performed trap loss spectroscopy within a range of 325 GHz below the Li(2S 1/2 ) + K(4P 3/2 ) and Li(2S 1/2 ) + K(4P 1/2 ) asymptotic states and observed more than 60 resonances, which we identify as rovibrational levels of 7 of 8 attractive long-range molecular potentials. The long-range dispersion coefficients and rotational constants are derived. We find large molecule formation rates of up to ∼3.5 × 10 7 s −1 , which are shown to be comparable to those for homonuclear 40 K * 2 . Using a theoretical model we infer decay rates to the deeply bound electronic ground-state vibrational level X 1 Σ + (v = 3) of ∼5 × 10 4 s −1 . Our results pave the way for the production of ultracold bosonic ground-state 6 Li 40 K molecules which exhibit a large intrinsic permanent electric dipole moment.