Study of fundamental limits of solid-state nuclear spin gyroscopy based on NV centers in diamond

旋转的精确检测是基础科学中的一个具有挑战性的问题，具有重要的应用意义。基于经典角动量守恒、量子标准和Sagnac效应的各种方法已经发展起来。最近，由于自主技术系统活动的激增，对精确和紧凑（!）惯性导航的需求正在增加。在其他技术中，观测核自旋系综进动是一种很有前途的精确测量自转的方法。目前的方法是基于热原子碱金属蒸气中超极化核自旋系综的锁相进动，但难以集成。在这里，我们的目标是在固体中实现这种方法，并展望开发紧凑的精密陀螺仪。我们的方法是基于金刚石中的氮空位（NV）中心，在环境条件下显示出无与伦比的光学和自旋特性。我们将利用核自旋集合作为旋转参考，使传感元件小型化并使其与芯片技术兼容。考虑到金刚石材料中核自旋的充分研究参数，估计旋转传感器的理论极限在每小时毫度的数量级，这使得该技术与基于光纤的环形激光光学陀螺仪相当，并且具有明显更小的尺寸优势。与微机电（MEMS）技术相比，核自旋陀螺仪将表现出明显更好的偏置稳定性特性。在项目过程中，金刚石材料将朝着核自旋系综的使用进行优化。该项目将包括研究开发新的旋转传感控制协议及其基本精度限制。项目的后半部分致力于研究利用新的控制方法和量子控制技术，如纠错和相干反馈，在可能的最佳传感协议中最小化和补偿漂移和系统效应。该项目将由两个实验室合作进行：德国的Wrachtrup教授和俄罗斯的Akimov教授。德国方面在开发传感协议和推进钻石材料方面有着广泛和长期的记录，而俄罗斯方面已经在进行钻石中NV陀螺仪测量原理证明的研究工作。通过合作，此次合作有可能通过探索新型金刚石材料和传感协议，实现与NV中心的旋转传感。

The precise detection of gyration is a challenging problem in basic science and of significant relevance for applications. A variety of methods based on classical angular momentum conservation, quantum standards as well as the Sagnac effect have been developed. Recently the demand for precision and compact (!) inertial navigation is increasing, caused by the surge of activities on autonomous technical systems. Among other technologies the observation of a nuclear spin ensemble precession is a promising method to measure rotation precisely. State of the art methods are based on phase-locked precession of ensembles of hyperpolarized nuclear spins in hot atomic alkali metal vapours, which however is hard to integrate. Here, we aim to realize such a method in a solid with the prospect to develop compact precision gyroscopes. Our approach is based on nitrogen-vacancy (NV) centers in diamond, shown to have unparalleled optical and spin properties under ambient conditions. We will utilize an ensemble of nuclear spins as reference for gyration which allows miniaturizing the sensing element and make it compatible with chip technology. Taking into account well-studied parameters of nuclear spins in the diamond material, the estimated theoretical limit of rotation sensor is on the order of millidegree per hour which puts this technology on par with fiber-based ring-laser optical gyroscopes with the advantage of a significantly smaller size. In comparison to the micro electromechanical (MEMS) technology, the nuclear spin gyroscope will show significantly better bias stability characteristics. In the course of the project, the diamond material will be optimized towards the usage of nuclear spin ensembles. The project will include research on developing novel control protocols for rotational sensing, and its fundamental precision limits. The latter part of the project is devoted to studies of minimizing and compensating the drifts and systematic effects in a possible optimal sensing protocol through utilizing novel control methods and quantum control techniques such as error correction and coherent feedback. The project will be pursued in a collaboration of two laboratories: Prof. Wrachtrup from the German side and Prof. Akimov from Russian side. The German side has a broad and longstanding track record in developing sensing protocols and advancing diamond materials, while the Russian side already has ongoing research work on proof of principles gyroscopic measurements with NV in diamond. By joining forces, this collaboration has the potential to enable rotational sensing with NV centers by exploring novel diamond materials and sensing protocols.