基于弱测量的量子通信过程的理论研究

发布时间：2018-05-07 18:29

本文选题：远程态制备 + 量子隐形传态　；参考：《华东师范大学》2017年硕士论文

【摘要】：本论文主要研究退相干环境下量子通信过程中量子态的保真度和量子Fisher信息,着重分析确定性远程态制备和量子隐形传态过程中弱测量对输出量子态的影响。一般来说,量子系统将不可避免与其周围的环境发生相互作用,从而导致量子体系相干性的损失。保真度常被用于度量量子通信过程的输出态与初始态之间的接近程度。噪声环境下如何提高量子态传输的保真度是量子通信领域的一个重要课题。基于弱测量技术,本文探讨了退相干影响下如何提高确定性远程态制备过程的保真度。首先构造了以EPR态为量子通道的确定性远程制备任意单比特态的量子线路,接着导出了 EPR纠缠通道经历推广振幅退相干情况下的量子保真度,然后还分析了-采用弱测量和测量恢复方法提高远程制备过程中平均保真度的可行性。研究表明,在仅有粒子2经过退相干通道时,推广振幅退相干下远程态制备过程的平均保真度与普通振幅退相干情形下的平均保真度表达形式完全相同。对于大部分给定的退相干参数,弱测量与测量恢复相结合的方法可增大量子态传输过程的保真度。本文还研究了远程态制备和量子隐形传态这两种在遭受环境噪声影响下量子Fisher信息的传输过程,并采用弱测量操作和/或测量恢复操作来对这两种方案传送的量子Fisher信息进行优化。数值分析表明,弱测量和测量恢复操作均可促进量子Fisher信息的传送;进一步研究发现,量子弱测量和测量恢复操作是两个不对称的操作,在优化过程中测量恢复操作起到更重要的作用。
[Abstract]:In this thesis, the fidelity of quantum states and the quantum Fisher information in the process of quantum communication in decoherence environment are studied, and the influence of weak measurement on the output quantum states in the process of deterministic remote state preparation and quantum teleportation is analyzed. Generally speaking, quantum systems will inevitably interact with their surroundings, resulting in the loss of coherence of quantum systems. Fidelity is often used to measure the proximity between the output state and the initial state of the quantum communication process. How to improve the fidelity of quantum state transmission in noisy environment is an important subject in the field of quantum communication. Based on the weak measurement technique, this paper discusses how to improve the fidelity of the deterministic remote state preparation process under the influence of decoherence. Firstly, a deterministic remote quantum circuit with EPR state as quantum channel is constructed, and then the quantum fidelity of EPR entangled channel with extended amplitude decoherence is derived. Then the feasibility of using weak measurement and measurement recovery method to improve the average fidelity in remote preparation is also analyzed. It is shown that when only particle 2 passes through the decoherence channel, the average fidelity of the extended amplitude decoherence is exactly the same as that of the ordinary amplitude decoherence. For most of the given decoherence parameters, the combination of weak measurement and measurement recovery can increase the fidelity of the quantum state propagation process. In this paper, we also study the transmission of quantum Fisher information under the influence of environmental noise, such as remote state preparation and quantum teleportation. The quantum Fisher information transmitted by these two schemes is optimized by weak measurement operation and / or measurement recovery operation. Numerical analysis shows that both weak measurement and measurement recovery operations can facilitate the transmission of quantum Fisher information. Further studies show that quantum weak measurement and measurement recovery operations are two asymmetric operations. Measurement and recovery operations play a more important role in the optimization process.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O413;TN918

【相似文献】