Effect of the Stark shift on entanglement in a double two-photon JC model

Abstract

Considering a double two-photon JC model, we investigate the entanglement between the two two-level atoms and that between the two cavity fields, and study the effect of the Stark shift on entanglement. The results show that, on the one hand the atom–atom and cavity–cavity concurrences evolve periodically with time and the periods are affected by the Stark shift; on the other hand, the two atoms are not disentangled at any time when the Stark shift is considered, and for large values of the Stark shift parameter, the two atoms can remain in a stationary entangled state. In addition, we find that the so-called entanglement sudden death can occur under appropriate conditions on the dynamic Stark shift for a certain initial state of the system.

Keywords:

• entanglement
• Stark shift
• a double two-photon JC model

Acknowledgements

This work has been financially supported by the National Natural Science Foundation of China (Grant No. 10374025), Hunan Provincial Natural Science Foundation of China (Grant No. 07JJ3013) and by the Foundation of Hunan Provincial Education Department of China (Grant Nos. 06A038, 06C080 and 06C174).