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Center for Nonlinear Studies |
Increasing interest in systems with narrow intercombination lines like strontium (Sr), ytterbium (Yb), and other alkaline-earth metal atoms has produced intense work toward cooling them to quantum degeneracy. We have observed Bose-Einstein condensation (BEC) of bosonic Sr-84. This isotope possesses ideal collisional properties for efficient evaporative cooling to quantum degeneracy despite its unfavorably low natural abundance (0.6%). We have also recently produced quantum degenerate samples of bosonic Sr-88 and fermionic Sr-87. These dramatic advances were possible largely because of the precise determination of the scattering lengths for all the Sr isotopes with two-photon photoassociation spectroscopy (PAS). Sr quantum fluids foster novel experimental possibilities, such as tuning atom-atom interactions with an optical Feshbach resonance near an intercombination line. Equally exciting theoretical proposals use quantum fluids made of alkaline-earth atoms to demonstrate quantum computation in optical lattices and create exotic quantum magnetism states.
Host: Xinxin Zhao