[above:] Observation of a laser cooling and trapping at 405nm, using the 4S-5P transition in potassium. Shown are four images: the left column are clouds trapped with the traditional cycling transition at 767nm, which couples the 4S_1/2 ground state to a 4P_3/2 excited state. The right column shows a cloud trapped on the open "blue" transition at 405nm, coupling to a 5P_3/2 excited state. The cloud is compressed, and about three times colder: as low as 65µK. For more details, see McKay et al, PRA 84, 063420 (2011).

[above:] The frequency with which an ultracold rubidium superfluid oscillates between the two sides of a barrier, as a function of barrier height. The white dots are measured frequencies, and the black lines are ab-initio theory calculations. JM is the two-mode Josephson Model, HD is a hydrodynamic model, and GPE is the Gross Pitaevskii equation. The barrier height is shown divided by the chemical potential of the condensate. For more details, see LeBlanc et al, PRL 106, 025302 (2011).