Spin Squeezing with Coherent Light via Entanglement Swapping
  We analyze theoretically a scheme that produces spin squeezing via the continuous swapping of atom-photon entanglement into atom-atom entanglement, and propose an explicit experimental system where the necessary atom-field coupling can be realized. This scheme is found to be robust against perturbations due to other atom-field coupling channels. 
Mehmet Emre Tasgin, Pierre Meystre
quant-ph