Ground-state entanglement of spin-1 bosons undergoing superexchange   interactions in optical superlattices
  We discuss a model with ultra-cold atoms confined in optical superlattices. In particular, we study the ground-state properties of two spin-1 bosons trapped in a double-well potential. Depending on the external magnetic field and biquadratic interactions different phases of magnetic order are realized. Applying von Neumann entropy and number of relevant orbitals, we quantify the bipartite entanglement between particles. Changing the values of the parameters determining superlattices, we can switch the system between differently entangled states. 
Artur Barasi\'nski, Wies{\l}aw Leo\'nski, Tomasz Sowi\'nski
quant-ph cond-mat.quant-gas