Spin mixing in colliding spinor condensates: formation of an effective barrier

The dynamics of F=1 spinor condensates initially prepared in a double-well potential is studied in the mean field approach. It is shown that a small seed of $m=0$ atoms on a system with initially well separated m=1 and m=-1 condensates has a dramatic effect on their mixing dynamics, acting as an effective barrier for a remarkably long time. We show that this effect is due to the spinor character of the system, and provides an observable example of the interplay between the internal spin dynamics and the macroscopic evolution of the magnetization in a spinor Bose-Einstein condensate.