级联四波混频系统中纠缠增强的量子操控

Quantum manipulation of entanglement enhancement in cascaded four-wave-mixing process

各类系统中的纠缠操控是量子信息科学的重要问题之一.本文研究了热原子蒸气的级联四波混频过程中产生的纠缠增强及纠缠增强的相位敏感特性.研究表明,该级联四波混频过程第二级输出的探针光和共轭光的量子纠缠较第一级明显增强,最大可达5 dB以上,且随着强度因子的增大可实现完美纠缠.文中还详细讨论了量子关联类型及纠缠大小与抽运光相位、非线性强度因子之间的变化关系,结果显示,由于纠缠增强及纠缠类型对抽运光相位的敏感性,通过控制相位和强度因子可改变光场噪声特性从而实现对探针光和耦合光之间纠缠增强、纠缠度大小、纠缠类型的量子操控.该理论研究对实验实现纠缠增强及双模压缩态压缩角、压缩度的光学参量操控具有重要的指导意义.

Entanglement manipulation in various systems is one of the important problems in quantum information science.In this paper,the phase sensitivity and entanglement enhancement of the cascade four-wave mixing of hot atomic steam are studied.The results show that the quantum entanglement of the probe light and the conjugate light output at the second level of the cascade four-wave mixing process is significantly stronger than that at the first level,and the maximum increment can reach more than 5 dB,and the perfect entanglement can be achieved by increasing the intensity factor.The relations of quantum correlation type and the size of the entanglement with the pump phase and the nonlinear intensity factor are also discussed in this work.The results show that because of the enhancement of entanglement and the sensitivity of entanglement type to pump phase,the light field noise characteristics can be changed by controlling the phase and intensity factors thus realize the enhancement of entanglement between the probe and coupling light and the quantum manipulation of entanglement extent and quantum entanglement type.The theoretical study is of important significance for guiding the experimental implementation of optical parameter manipulation of entanglement enhancement,compression angle and compression degree of two-mode compression state.