Bose-Einstein condensation: cold new results

Summary form only given.We have been performing a series of experiments with Rb-97 bose condensates confined in magnetic traps. Much of our recent experimental effort has been concentrated on experiments with two distinguishable but mutually overlapping condensate species simultaneously trapped in a TOP trap. We use the |F=1,m=-1> and |F=2,m=1> spin states of the Rb-87. The two spin states have nearly the same magnetic moment, which means that, in the absence of interactions, they would be spatially completely overlapping at the center of a magnetic trap. It remains to be seen whether mutual interactions will favor instead a spontaneous phase separation. It is already clear that the overlapping two-condensate system remains stable long enough to resonantly couple the two species with a two-photon microwave drive. The system thus is an excellent workshop for exploring the nature of the relative phase of two condensates.