We distinguish two types of spatial separation exhibited by atomic trap Bose-Einstein condensates: potential separation, in which case the condensates diffuse into each other as the trap is opened adiabatically, and phase separation, in which case the separation persists in the absence of external potentials. We discuss relevant features of the dynamics and statics of the phase separation of dilute condensates.

• Received 26 August 1997

DOI:https://doi.org/10.1103/PhysRevLett.81.5718