利用纠缠密度研究光子禁带系统的纠缠演化特性

Evolution of Entanglement Density in Band Gap

研究了一个二能级原子在光子禁带模型中的原子与热库间及热库模式间的纠缠动力学行为。利用全局纠缠的方法,引出与热库模式相关的纠缠密度。研究发现,当禁带是完美带隙时,会出现稳态原子布居数俘获现象,从而抑制原子的自发辐射效应,防止了信息传输过程中信息的流失。原子与热库模式之间的纠缠密度以及热库模式与模式之间的纠缠密度会随着原子与热库之间耦合强度的增加而增大。当取长时极限时,原子与热库模式之间的纠缠减为零。热库模式与模式之间在强耦合情况下,由于拉比分裂的作用,在两个对称模式间会形成较强的纠缠;在弱耦合情况下,只能在中心频率处形成纠缠。

We investigate the entanglement dynamics behavior between one two-level atom and reservoir in photonic band gap model.Using the method of global entanglement,we get the density of entanglement of correlative with the reservoir modes.It is found that,when the forbidden band is a perfect band gap,there is a permanently trapped atomic population,which inhibiting the atomic spontaneous radiation effect and preventing the loss of information in the process of information transmission.The density of entanglement between atoms and the reservoir and the density of entanglement among reservoir modes both increase with the coupling strength between the atom and reservoir.When we take long time limit,the density of entanglement between atoms and the reservoir can disappear.For the strong coupling case,due to the Rabi splitting,there is a stable entanglement between two symmetrical modes.For the weak coupling case,the entanglement call only occur between the modes in the vicinity of central frequency.