Reply to the ``Comment on `quantum backaction of optical observations on   Bose-Einstein condensates' ''
  In our paper we estimated the quantum backaction of dispersive imaging with off-resonant light on Bose-Einstein condensates. We have calculated the rates of the two processes involved, phase diffusion and depletion of the condensate. We compare here the depletion rate obtained within our model limitations to the Rayleigh scattering rate, both having the same physical origin: dispersive interaction of light with matter. We show that residual absorption sets indeed the limit of dispersive imaging. 
U. Leonhardt, T. Kiss and P. Piwnicki