Quantum Operations and Imaging Using Highly Coherent Scanning Probe Spins

光学活性自旋缺陷，如金刚石中的氮空位(NV)中心，可以作为量子传感、磁场成像和量子计算的有力工具。通过在固态扫描探针的尖端加入NV中心，NV中心被用作具有纳米空间分辨率的敏感磁场传感器。然后，可以在磁性样品的表面上扫描NV中心，并且可以使用光学和共振微波来测量NV中心和磁场之间的后续相互作用。除了量子传感和成像，扫描尖端上的NV中心也可以用于实现表面代码量子计算。可扩展的量子计算体系结构要求两个或多个量子比特(量子比特)之间的量子相互作用是高度关联的，即实现量子纠缠。这个可移动的探测器将允许位于尖端的NV中心耦合样品中的近表面量子比特，使它们纠缠在一起，从而实现本地量子操作。这个项目将利用我们在伦敦纳米技术中心可用的一种新的操作最先进的扫描和成像仪器。最初，该仪器将用于对生物学和凝聚态物理的有趣样品进行成像，例如新型磁性材料和自旋标记的生物分子。将研究近表面NV中心的稳定性，以及可能的碳化硅缺陷，并将优化制造技术，以产生具有优越自旋特性的缺陷。该仪器还可以用来开始使用可移动的探测自旋实现材料中施主自旋之间的自旋-自旋耦合和纠缠的介绍性工作。

Optically active spin-defects, such as the nitrogen vacancy (NV) centre in diamond, can be used as powerful tools for quantum sensing, magnetic field imaging and quantum computation.By incorporating NV centres at the tip of solid-state scanning probes, NV centres have been used as sensitive magnetic field sensors with nanoscale spatial resolution. The NV centre can then be scanned over the surface of a magnetic sample and the consequent interaction between the NV centre and the magnetic field can be measured using optical light and resonant microwaves. As well as quantum sensing and imaging, NV centres on scanning tips can be used for the real-isation of surface-code quantum computation. Scalable quantum computing architectures require the quantum interaction between two or more quantum bits (qubits) to be highly correlated, i.e. the realisation of quantum entanglement. The movable probe would allow the NV centre in the tip to couple near-surface qubits in the sample, entangling them and allowing for the implementation of local quantum operations.This project will make use of a new operational state-of-the-art scanning and imaging instrument available to us in the London Centre of Nanotechnology. Initially this instrument will be used to image interesting samples to biology and condensed matter physics, such as novel magnetic materials and spin-labelled biological molecules. The stability of near-surface NV centres, as well as possibly silicon carbide defects, will be investigated and the fabrication technique willbe optimised to create defects with superior spin properties. This instrument can also be used to start introductory work on achieving spin-spin coupling and entanglement between donor spins in a material using a movable probe spin.