Bubble formation in a two-component BEC
This animation shows how two different species of rubidium separate into distinct layers, or "bubbles," when they simultaneously Bose-condense, provided they repel one another strongly enough. The density profiles of Rb-85 (blue) and Rb-87 (red) are shown elolving as the number of condensed atoms grows from a small initial sample. The final configuration, with many interleaved layers of the two condensates, is far from the ground state of this immiscible system, a result of the non-equilibrium process that produced the gas. The physics is described in more detail here. Click on the figure below to see the movie