利用动力学去耦合脉冲增大和调节量子相干性和三体纠缠

Ehancement of quantum coherence and three-body entanglement by dynamical decoupling pulses

摘要:

本文研究了动力学去耦合脉冲对腔量子电动力学系统中量子相干性, 量子失谐和量子纠缠的影响, 发现动力学去耦合脉冲不仅能够增大系统中两原子之间的量子相干性, 同时也能增大它们之间非经典关联（量子失谐和量子纠缠）. 同时, 凭借迹距离的方法, 探讨了动力学去耦合脉冲增大两原子之间量子相干性的原因, 通过探究可以看出动力学去耦合脉冲能够控制和加速量子信息从其他子系统回流到两个原子中去, 并减少两原子子系统和其他子系统之间的量子信息流动, 从而增加两原子间的量子相干性和非经典关联. 最后, 利用保真度的方法研究了系统中三体纠缠出现的情况, 结果显示在不同的时间, 系统中会出现三体纠缠, 特别值得指出的是, 可以通过动力学去耦合脉冲来调节和增加系统中三体纠缠出现的时间.

Abstract:

The influence of dynamical decoupling pulses on the quantum coherence, quantum entanglement and quantum discord in cavity quantum electrodynamics system is investigated. We find that the quantum coherence and non-classical correlations (entanglement and quantum discord) between two atoms can be increased by applying a train of dynamical decoupling pulses. Furthermore, by making use of the trace distance, we also explore the reason for enhancement of quantum coherence of two atoms. It is shown that the dynamical decoupling pulses can control and accelerate the return of quantum information from other subsystems to two atoms, and reduce the flow of quantum information between two atoms and other subsystems, which leads to the increase of quantum coherence and non-classical correlations between two atoms. Finally, we investigate the three-body entanglement of the system by using state preparation fidelity. It demonstrates that the genuine three-body entanglement may emerge in the system during the evolution of time. In particular, the period of emergence of three-body entanglement can be adjusted and enhanced by dynamical decoupling pulses.