Remote atom entanglement in a fiber-connected three-atom system
  An Ising-type atom-atom interaction is obtained in a fiber-connected three-atom system. The interaction is effective when $\Delta\approx \gamma _{0}\gg g$. The preparations of remote two-atom and three-atom entanglement governed by this interaction are discussed in specific parameters region. The overall two-atom entanglement is very small because of the existence of the third atom. However, the three-atom entanglement can reach a maximum very close to 1. 
Guo Yan-Qing, Chen Jing, Song He-Shan