T-C模型中三比特完全纠缠态与W-纠缠态的产生

在两个定态全同二能级原子与单模光场共振相互作用的Tavis-Cummings模型中，原子与场间相互作用与原子间相互作用相差较大时，体系可产生三比特完全纠缠态。通过分析得出，该体系的三比特纠缠随二原子和单模场所处的初始叠加状态、二原子间及原子与光场间的耦合系数的变化而变化。特别地，在特定的初始状态下，该体系可产生W-纠缠态，而产生W-纠缠态的必要条件是原子之间的耦合要比原子与场之间的耦合小得多。

Generation of Three-qubit Entangled and W-entangled State in Tavis-Cummings Model

The three-qubit entangled state in Tavis-Cummings model for two identically steady two-level atoms interacting with single mode field can be generated when the atom-field interaction is far from atom-atom interaction.By analyzing three-qubit entanglement of the system,we obtain that the entanglement of the system will change with the variation of system initial state,coupling coefficients between atom and field or atoms.Especially,when the initial state is special,the system will stay in W-entangled state.The necessary condition for generating W-state is that the coupling constant between two atoms is more less than that of between an atom and field.