Maximal entanglement of two spinor Bose-Einstein condensates
  Starting with two weakly-coupled anti-ferromagnetic spinor condensates, we show that by changing the sign of the coefficient of the spin interaction, $U_{2}$, via an optically-induced Feshbach resonance one can create an entangled state consisting of two anti-correlated ferromagnetic condensates. This state is maximally entangled and a generalization of the Bell state from two anti-correlated spin-1/2 particles to two anti-correlated spin$-N/2$ atomic samples, where $N$ is the total number of atoms. 
Michael W. Jack and Makoto Yamashita