金刚石氮空位色心体系中的纠缠制备、表征和保护

量子纠缠是量子力学的基石，是量子物理与经典物理最根本的区别。它揭示了量子实体间可能存在的深刻且略带神秘的联系，从而挑战了传统关于空间分离和因果关系的观念。这种独特的特性不仅在理论上具有重要意义，而且被视为一种宝贵资源，推动了量子信息科学的进步。在量子计算领域，利用量子比特的纠缠状态能够进行并行计算，大大加快了某些问题的解决速度，超越了传统计算的能力。量子通信则通过纠缠态实现了量子密钥分发，提供了理论上绝对安全的通信手段。此外，量子纠缠在突破精密测量的经典技术限制方面也发挥了关键作用。
然而，尽管量子纠缠为量子技术的发展提供了巨大潜力，但在实际应用中有效制备和保护纠缠态的挑战依然存在。纠缠态极其脆弱，容易受到外界环境的干扰，这限制了其在实际应用中的效率和可靠性。另外，虽然纠缠已经在理论和实验物理学中得到广泛研究，人们对量子纠缠的深层机制的理解仍非常有限。因此，深入研究量子纠缠对于推动量子信息技术领域的发展至关重要。
本论文主要讨论了作者围绕量子纠缠展开的相关研究。在成功自主搭建基于金刚石氮空位色心的实验平台之后，作者的主要研究工作包括以下几个方面：（1）研究了氮空位色心电子自旋的光学极化机制以及核自旋的动态核极化过程。为此，我们分别构建了数学模型并进行了数值仿真。通过脉冲激光技术，显著提高了电子自旋和核自旋的初始化效率。这一进步不仅增强了系统的信噪比，也为制备高保真度的纠缠态奠定了坚实基础。（2）研究了纠缠结构的表征方法。利用基于前馈神经网络的机器学习分类器，成功地对理论数据中的纠缠结构进行了表征。此外，通过针对实验系统噪声参数的理论数据预处理，该方法在表征真实实验数据的纠缠结构时展现出了可靠性。（3）研究了一种保护纠缠的方法。该方法融合了基于混合量子经典算法的量子自编码器技术和无消相干子空间的理念，能够将纠缠态压缩编码至相干时间较长的子空间中。在需要时，通过解码操作可以恢复纠缠态，从而有效延长了纠缠的寿命。
上述研究成果将有助于促进量子纠缠在量子信息领域中的应用，为量子信息技术的发展提供技术基础。我们将继续在这一领域努力，以期将这些研究成果应用于量子精密测量等领域。

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