多模简并多光子Tavis-Cummings模型中的量子纠缠特性

利用冯·纽曼约化熵理论研究了多模相干态光场与两等同二能级原子简并多光子相互作用系统量子纠缠演化特性,得到了多模光场量子纠缠的解析表达式,并给出了双模光场与两原子相互作用时量子纠缠的数值计算结果.结果表明:量子纠缠随着光子简并度的增大而增强;随着初始平均光子数的增加,量子纠缠演化的周期性变得越来越明显;当场与原子远离共振时,量子纠缠随着频率失谐量的增大而减弱;当失谐量足够大时,场与原子几乎总是处于纠缠状态.这些结论对于纠缠态或纯态的制备及获取光学系统中的量子信息研究中有一定参考价值.

Quantum Entanglement Properties in Multimode Degenerate Multi-photon Tavis-Cummings Model

The evolution properties of quantum entanglement in a system of multimode coherent field interacting with two identical two-level atoms through degenerating multi-photon process are investigated using the Von Neumann quantum reduced entropy theory, and the analytical expression of quantum entanglement and the numerical calculation results for two-mode field interacting with the atoms are obtained. The results show that: the quantum entanglement will strengthen with the enhancement of the photon degeneracy; the periodicity of the quantum entanglement will become more and more apparent with the increasing of the average photon number; when the field and the atoms are far from resonance, the quantum entanglement will decrease with the increase of the frequency detuning; when the frequency detuning is large enough, the field and the atoms are nearly always in entangled states. These results are useful for the preparation of the entangled states or pure states and for quantum information in optics systems.