Preparation of NOON State Induced by Macroscopic Quantum Tunneling in an   Ising Chain
  In this brief report, we propose a possible way, theoretically and experimentally, to generate a NOON state of the two degenerate ferromagnetic ground states of the Transverse Ising Model. In our scheme we employ the macroscopic quantum tunneling (MQT) effect between the two degenerate ferromagnetic ground states to realize the NOON state. Our calculation about the MQT process is based on a higher-order degenerate perturbation method. After doing a transformation, the MQT process could also be treated as the hopping of individual virtual fermions in the spin chain, which will leads to an analytical description of tunneling process. The experimental feasibility for generating the NOON state is discussed in the setup of linear ion trap. 
Chun-Li Zang, Jing Yu, Wan-Li Yang, Mang Feng, and Su-Peng Kou
quant-ph physics.atm-clus