Atom optics with rotating Bose-Einstein condensates
  The atom optics of Bose-Einstein condensates containing a vortex of circulation one is discussed. We first analyze in detail the reflection of such a condensate falling on an atomic mirror. In a second part, we consider a rotating condensate in the case of attractive interactions. We show that for sufficiently large nonlinearity the rotational symmetry of the rotating condensate is broken. 
I. Josopait, L. Dobrek, L. Santos, A. Sanpera, M. Lewenstein