Nonequilibrium dynamics induced by miscible-immiscible transition in binary Bose-Einstein condensates

We have observed and characterized the nonequilibrium spatial dynamics of a two-component Rb-87 Bose-Einstein condensate (BEC) that is controllable switched back and forth between the miscible and immiscible phases of the phase separation transition by changing the internal states of the Rb-87 atoms. The subsequent evolution exhibits large scale oscillations of the spatial structure that involve component mixing and separation. We show that the larger total energy of the miscible system results in a higher oscillation frequency. This investigation introduces a new technique to control the miscibility and the spatial degrees of freedom in atomic BECs.