多场操纵金刚石NV色心电子布居数的量子信息处理

In this project, cutting-edge technologies for quantum coherent control are applied in one of the popular solid-state quantum systems. We will concentrate on the application of electronic population transfer in diamond NV center controlled by multiple external fields. The ultimate target is to optimize the theoretical scheme of coherent controlling solid-state quantum system, and to verify the advantage of the optimized theoretical scheme by detecting the fluorescence characteristics of NV certer. Theoretically, we will firstly set up a physical model for quantum coherent control in diamond NV center, wherein the population transfer of electrons is controlled by multiple fields. In this model, the dynamics of electronic population transfer will be optimized by properly controlling the external fields. Thus, it is more convenient for us to realize fast quantum logic gates and prepare the spin-photon entanglement with high efficiency. Secondly, the interaction between the diamond NV centre and a single-mode cavity will be considered. We will investigate the cavity quantum electrodynamics based on the optimized theoretical scheme with multiple fields. This progress can be benefit for us to realize the high-efficiency single photon. Experimentally, we will firstly optimize the fluorescence characteristics by quantitatively controlling the local variables of the diamond NV centre. Then according to the result of the optimized theoretical scheme, we will adjust the directions, frequencies, intensities and sequences of the applied magnetic fields, microwave fields, electric fields and laser fields to realize the optimized population transfer. We will detect the fluorescence characteristics of the NV center to obtain the variable-function relationship which are relative to quantum efficiency of the diamond NV center. Therefore, the advantage of the optimized theoretical scheme with multiple fields will be verified. Our research will provide a reliable theoretical and experimental evidence for the application of electronic population transfer with multiple fields in the solid-state quantum systems.

本申报项目将当前热门的固态量子系统与新型的量子相干调控技术相结合，研究多场操纵金刚石NV色心电子布居数的应用，优化固态量子系统相干调控的理论方案，并在实验上验证理论方案的优越性。理论上，我们将建立多个外场控制NV色心的理论模型，通过优化多个外场得到调控NV色心电子布居数的最优化理论方案。在最优化理论方案的基础上，探讨快速量子逻辑门的操作和高效率的自旋-光子纠缠态的制备，并研究NV色心与光学腔的相互耦合作用，探讨多场操纵最优理论技术的腔量子电动力学过程，实现高品质单光子源的制备。实验上，我们将定量控制NV色心的局域变量，优化样品荧光特性，利用理论结果，调节外加磁场、微波场、电场、光场的方向、频率、强度、作用次序等，实现NV色心电子布居数最优化控制，测量相应NV色心的荧光特性，得到量子效率的变量-函数关系，验证理论方案的优越性。该项目将为多场控制固态量子系统提供优化的理论和实验依据。

在量子信息领域，由于量子系统的调控受退相干时间的制约，因此快速、有效地实现固态量子点的相干调控，对量子计算、量子保密通讯的实现具有重要意义。本项目主要研究了如何利用多个外场控制固态量子系统的布居数相干转移。通过理论建模，分析不同调控技术的优缺点，构建多个外场控制固态量子系统的最优技术，根据理论最优技术，设计实验方案，通过探测分析固态量子系统的荧光性质，验证理论方案的有效性。通过理论建模和数值分析，我们得到量子路径渡越技术是实现固态量子系统相干调控的最优技术。基于该研究成果，我们首次证实了产生于自旋轨道相互作用的Dzyaloshinskii-Moriya相互作用不仅不会破坏量子相干调控，还能提高相干调控的保真度。通过分析量子系统演化的主方程，讨论环境耗散对系统布居数演化的影响，我们证实了量子路径渡越技术相对于其他调控技术而言，具有更强的抗噪能力。实验上，我们根据理论模型，通过改变激光场、电场，以及改变金刚石NV色心的衬底，将金刚石与不同二维材料耦合，通过分析金刚石NV色心的荧光光谱和单光子计数，研究固态量子系统的相干调控。重点开展了单晶GeSe、石墨烯等二维材料的大面积制备技术、电子能带结构及其相关的光-电子性质研究，电场调控金刚石NV色心电子布居数的研究，以及金刚石NV色心耦合二维材料联合发光研究，并通过控制电场和激光场，提高了金刚石NV色心的单光子产生效率。