A two atomic species superfluid
  We produce a quantum degenerate mixture composed by two Bose-Einstein condensates of different atomic species, 41 K and 87 Rb. We study the dynamics of the superfluid system in an elongated magnetic trap, where off-axis collisions between the two interacting condensates induce scissors-like oscillation. 
G. Modugno, M. Modugno, F. Riboli, G. Roati, M. Inguscio