连续变量级联量子隐形传态系统的性能优化研究

Sequential quantum teleportation of continuous variables not only offers an effective quantum relay for long-distance quantum communication and quantum internet, but also provides a feasible way for measurement-based quantum computation and universal quantum processor. Because it is powerful to conduct deterministic and unconditional reconstruction of any arbitrary unknown quantum state between arbitrary locations. Therefore, it is indispensable for quantum telecommunication, quantum tele-computation, and quantum remote control. This project proposes an approach to optimize the performance of the sequential quantum teleportation for continuous variables by introducing entanglement distillation following a quantum frequency comb and combing frequency-resolved broadband homodyne detection as well as signal demodulation technique. Optimization via entanglement distillation based on photon subtraction and noiseless linear amplification will be intensely studied. The fidelity of the sequential quantum teleportation system for continuous variables will be optimized by adjusting the related parameters based on the results of numerical simulations. The uniqueness of this project is to dramatically simplify the optical structure of a continuous-variable sequential quantum teleportation and optimize its performance by just inserting the entanglement distillation unit after the quantum frequency comb, which significantly enhance the feasibility of such systems in quantum information science.

连续变量级联量子隐形传态，可在任意空间对任意量子态实现确定性的、无条件的重建，为远距离量子通信及量子互联网提供了有效的量子中继方式，也为基于测量的量子计算和通用量子可编程处理器的实现提供了可行方案。因此在远程量子通信、远程量子计算和量子远程控制中起着至关重要的作用。本项目基于量子光频率梳，结合频率可分辨的宽谱零差检测和信号解调技术，利用纠缠蒸馏方法，提出一种实现连续变量级联量子隐形传态系统结构简化及性能优化的方案。通过对系统建模，定量分析基于减光子和无噪声线性放大的纠缠蒸馏方法对级联量子隐形传态系统性能的优化程度。基于数值模拟结果，选择合适的参数实现级联量子隐形传态系统的性能优化。本项目的显著特点是通过在量子光频率梳后引入一个纠缠蒸馏装置即可增强量子光频率梳输出的所有相关频率分量之间的纠缠度，在实现连续变量级联量子隐形传态系统性能优化的同时，极大简化系统的光学结构，提高其可行性。

作为远距离量子通信及量子网络的有效中继技术，连续变量级联量子隐形传态系统是量子信息技术的重要组成部分。本课题探索了基于连续变量级联量子隐态传态系统的性能优化方案。通过在量子光频率梳上制备非高斯量子态，即薛定谔猫态，再利用光分束器结合两个薛定谔猫态，提出了制备相关增强的量子纠缠源协议。与已报道的其他纠制备缠源的方法相比，本项目中得到的纠缠源的对数负性高于双模压缩真空态及减光子的双模压缩真空态，结构上优于基于无噪声线性放大技术的纠缠源。从而解决了影响连续变量级联量子隐形传态系统性能的核心问题。同时，基于量子光频率梳提出了一种奇偶性可保持的薛定谔猫态放大协议，为量子信息技术提供新的制备量子源方法的同时，也开创了量子光频率梳的新应用。