与两等同Bell态纠缠原子相互作用光场的量子场熵

利用全量子理论,并通过数值计算,研究了初始处于Fock态的单模光场与两等同双能级纠缠原子单光子共振相互作用过程中单模光场量子场熵的时间演化特性.结果发现:当两原子初始处于第一种Bell态时,光场量子场熵的时间演化周期为π/g2(2n+1);随着初始光强的增大,光场与原子之间的量子纠缠现象减弱;特别是当时间t为演化周期的整数倍时,场－原子系统处于退纠缠状态.当两原子初始处于第二种Bell态时,光场量子场熵不随时间变化,恒为零.当两原子初始分别处于第三种和第四种Bell态时,光场量子场熵的时间演化曲线呈现不等幅周期振荡现象;并且随着初始光场光子数的增加,光场量子场熵的振荡周期逐渐增大,但振荡幅值逐渐减小.

Study on Quantum Entropy of Field Interacting with Two Identical Entangled Atoms in Bell States

The evolution properties of quantum entropy of the field in the Fock state interacting resonantly with a pair of identical two-level entangled atoms in Bell states are studied by utilizing of the complete quantum theory and by the numerical method. The evolution periodicity of quantum field entropy is πg2(2n+1) when the two atoms are initially in the first kind of Bell state. The quantum entanglement between the field and the atoms decreases with the increase of the initial field intensity, and the field is completely disentangled from the atoms when the time is a whole-number multiple of the evolution peridicity. The quantum field entropy isn′t change with the time and always remains at zero when the two atoms are initially in the second kind of Bell state. The evolution curves of quantum field entropy periodically oscillates with unequal amplitude when the two atoms are initially in the third and the fourth kind of Bell state respectively, and the periodicity of the oscillation of the quantum field entropy increases with the increases of the initial photon number, while the amplitude of the oscillation decreases. The Bell states composed of a pair of identical two-level atoms can be partially distinguished based on the evolution properties of quantum field entropy above.