Paper Presented at the Pan-Pacific Conference Describes Mixtures of BEC

PI Sui-Tat Chui of the University of Deleware describes a paper he presented at the 2nd Pan-Pacific Workshop on Research in Microgravity discussing the behavior of mixtures of Bose-Einstein condensates. The article defines regions of metastability of the quantum spinoidal phase and exact solutions of the two-component Gross-Pitaevskii equation. When a mixture of two Bose-Einstein condensates phase separates, it exhibits a periodic density modulation for a very long time. The paper reports that there are exact solutions of the nonlinear equations that govern the physics of the system that exhibit the periodic density modulation. These solutions demonstrate the metastability of the system, and they show that the nonlinearities do not destroy the periodic state. Furthermore, these exact solutions are found only for certain concentrations of the mixtures. This dependence on concentrations suggests that the metastability exists only in certain regions of the phase diagram for the mixtures. This paper has been accepted for publication in Physical Review Letters.