Bose-Einstein Condensation of Alkaline Earth Atoms: ⁴⁰Ca

We have achieved Bose-Einstein condensation of ⁴⁰Ca, the first for an alkaline earth element. The influence of elastic and inelastic collisions associated with the large ground-state s-wave scattering length of ⁴⁰Ca was measured. From these findings, an optimized loading and cooling scheme was developed that allowed us to condense about 2×10⁴ atoms after laser cooling in a two-stage magneto-optical trap and subsequent forced evaporation in a crossed dipole trap within less than 3 s. The condensation of an alkaline earth element opens novel opportunities for precision measurements on the narrow intercombination lines as well as investigations of molecular states at the ¹S-³P asymptotes.