频率变化的相干态光场中两原子纠缠演化

The Entanglement of Two Atoms in a Coherent Field of Time-Varying Frequenry

研究了频率变化的相干态光场中两个二能级原子的纠缠演化,主要讨论了光场频率随时间作正弦调制和脉冲调制两种典型情况下两原子纠缠随时间演化的特点。数值计算结果表明,当光场频率随时间作正弦调制时,光场频率,光场平均光子数均对原子纠缠演化有影响,且在少光子数的情况下,在光场频率变化的半周期内纠缠值出现小幅快速振荡;而当光场频率随时间作脉冲调制时,由于脉冲频率的突变,也在脉冲出现的区间内诱导出了原子纠缠值的小幅快速振荡现象。分析表明光场频率的改变可以改变原子相干性,进而改变了原子间纠缠效应,这对量子信息技术中纠缠制备与控制有积极意义。

The entanglement of two two-level atoms in a coherent field of time-varying frequency have been investigated. The properties of the entanglement of two atoms for two typical - the frequency of field varying with time in the forms of sine function and rectangular pulses have been considered. The numerical calculation show. for the frequency changing with time in sinusoidal form, the frequency and the mean photon number of field affect the entanglement of two atoms and in the condition of a small number of photons, small-amplitude fast oscillations occur during half period. For the frequency changing with time in rectangular form, The sudden jumping of the field with rectangular pulsed frequency-modulation can change the coherence of the two atoms, and induce the new entanglement phenomenon of the two atoms. The entanglement of two atoms is small-amplitude fast oscillations during the pulse. The changes of optical field frequency can change the coherence of atoms, and then change entanglement between atoms. The paper prove to be constructive in entanglement preparation and control in quantum information technique.