We investigate the pairwise entanglement and global entanglement in a generalized Jaynes-Cummings model, which can be used to realize Greenberger-Horne-Zeilinger （GHZ） entangled state （Zheng S B 2001 Phys. Rev. Lett. 87 230404）. Our results show that the W-type entangled states cannot be generated based on the model. The dependences of entanglement on Rabi frequency λ and dipole-dipole coupling strength Ω are given. It is found that there exists the quantum phase transition when λ= Ω. For typical experimental data, the critical temperature for pairwise entanglement is on the order of 10^-6 K. Based on these results, two strategies that overcome decoherence are proposed.
In this paper the so-called sudden death effect of entanglement is investigated in a quantum model. The results show that one can expect the resurrection of the original entanglement to occur in a periodic way following each sudden death event. The length of the time interval for the zero entanglement depends not only on the degree of entanglement of the initial state but also on the initial state.
