Rayleigh-Taylor instability of binary condensates

We propose a scheme to initiate and examine Rayleigh-Taylor instability in the two species Bose-Einstein condensates. We identify ${}^{85}$Rb-${}^{87}$Rb mixture as an excellent candidate to observe it experimentally. The instability is initiated by tuning the ${}^{85}$Rb-${}^{85}$Rb interaction through magnetic Feshbach resonance. We show that the observable signature of the instability is the damping of the radial oscillation. This would perhaps be one of the best controlled experiments on Rayleigh-Taylor instability. We also propose a semi analytic scheme to determinate stationary state of binary condensates with the Thomas-Fermi approximation for the axis symmetric traps.