Dynamical Instability of a Doubly Quantized Vortex in a Bose-Einstein   condensate
  Doubly quantized vortices were topologically imprinted in $|F=1>$ $^{23}$Na condensates, and their time evolution was observed using a tomographic imaging technique. The decay into two singly quantized vortices was characterized and attributed to dynamical instability. The time scale of the splitting process was found to be longer at higher atom density. 
Y. Shin, M. Saba, M. Vengalattore, T.A. Pasquini, C. Sanner, A.E.   Leanhardt, M. Prentiss, D.E. Pritchard, W. Ketterle