提高测量诱导的NV色心固态电子自旋纠缠产生效率的关键技术研究

Solid-state electron spin in diamond, known as NV centre, is now becoming one of most extensively studied physical system in quantum computing due to its favorable property in quantum state preparation, read-out, manipulation and long coherence time. Currently, the most important challenge in NV based quantum computing research is extension of quantum control from single NV to multi-NV. For physical realization, this needs generate entanglement of different NV centres effectively. Among different theoretical proposals, the measurement-induced entanglement generation is believed to be most promising candidates for this purpose. By measuring a joint property of photons emitted by NV centres, entanglement could be generated without directly strong interaction between them, however, based on the state-of-art experimental techniques, the practical rate of entanglement generating is pretty small, even for a single NV centre pair such entanglement rate is much small than the theoretical limit, and therefore far from the requirements of scalable quantum computing. This research would concentrate on some keys technical issue in such entanglement generating process which includes: 1, how to increase the photon emission of the NV centre, 2, how to improve quantum efficiency of joint-measurements, 3, how to realize fast modulation of the NV centre energy structure. By improving the existing technology as well as developing new methods, the entanglement generating rate of the NV centre pair is expected to be increasing significantly, this would leads to breakthrough in scalable quantum computing based on NV centres potentially.

金刚石NV色心的固态单电子自旋量子态，凭借其极其优良的制备，探测，操控以及理想的量子相干时间，近年来成为固态量子计算实验研究的重要方向。当前，基于NV色心的量子计算研究的最大挑战就是实现从单个NV色心向多NV色心的扩展，其核心就是纠缠态的产生。当前众多实现这一目标的方案中，基于测量的纠缠产生最受关注，该方案的实现关键在于对两个NV色心发出的光子对进行特殊的联合测量。然而受限于现有的实验技术，仅是两个NV色心在单位时间内产生纠缠的成功概率极低，远小于理论极限，因此无法满足开展可扩展性量子计算的需要。本项目拟对相关物理过程中的若干关键技术展开研究。包括：1）如何提高NV色心发光效率。2），如何提高关联测量的量子效率。3），如何实现NV色心能级的快速调制。通过在以上三个方面进行技术改进及创新，最终力求有效提高单位时间内NV色心对纠缠态产生率，从而为实现基于NV色心的可扩展量子计算提供潜在的技术突

基于金刚石NV色心的固态单电子自旋量子态，凭借其优良的制备、探测、操控以及理想的量子相干时间，近年来成为固态量子计算实验研究的重要方向。本项目以实现NV色心发光效率的提高、光子关联测量量子效率的提高以及对NV色心激发态的量子调控为目标，最终实验实现单位时间内两个NV色心纠缠态产生率的提高，并开展相关的可扩展量子计算实验研究。拟对其相关物理过程中面临的若干关键技术展开研究，具体内容包括：（1）设计与制作光学微腔结构，提高NV色心激发态光子发射效率；（2）设计与加工光学微结构，提高关联测量的量子效率；（3）基于斯塔克效应的激发态能级快速调制技术。本项目通过在以上三个方面进行技术改进及创新，实现了课题的关键技术指标，相关技术部分结果已经以国际物理学一流期刊的方式加以体现，为将来量子计算、量子精密测量等课题研究提供了技术支持。