Generation of concatenated Greenberger-Horne-Zeilinger-type entangled   coherent state based on linear optics
  The concatenated Greenberger-Horne-Zeilinger (C-GHZ) state is a new type of multipartite entangled state, which has potential application in future quantum information. In this paper, we propose a protocol of constructing arbitrary C-GHZ entangled state approximatively. Different from the previous protocols, each logic is encoded in the coherent state. This protocol is based on the linear optics, which is feasible in experimental technology. This protocol may be useful in quantum information based on the C-GHZ state. 
Rui Guo, Lan Zhou, Shi-Pu Gu, Xing-Fu Wang, and Yu-Bo Sheng
quant-ph