Quantum Information with NV Centres

QINVC的目的是利用钻石中带负电荷的氮空位(NV)色心在室温和低温下的优越量子相干，用于量子信息处理(QIP)。就相干性而言，这个系统确实是最好的固态量子系统之一，易于被ESR操纵，并且可以通过光学显微镜寻址到单自旋。我们的项目首先关注QIP(WP1)的两种混合策略。第一种方法是制造规则的单NV中心阵列，使用放置在悬臂梁顶端的可移动NV自旋执行栅极操作，足够近的距离通过磁偶极相互作用与晶格上的NV自旋纠缠。这种制造方法是基于脉冲离子束注入，通过穿过AFM悬臂梁尖端的小孔，或通过沉积在钻石样品表面的掩膜的空洞。第二种策略基于电路量子电动力学和NV自旋系综来实现QIP的混合架构：跨声子量子比特通过嵌入其中的谐振器耦合到NV自旋系综上。NV自旋将被用作传输量子比特的长相干时间量子存储器，用于处理量子信息。QINVC将在WP2中研究NV中心在低温下的光学性质。WP2的第一个目标是将常温下用于控制电子和核自旋的光学技术转移到低温，目的是将它们应用于混合量子电路(WP1)。第二个目标是研究NV中心系综建立光学光子量子存储器的潜力。这些雄心勃勃的目标将要求使用最先进的方法和其他方法优化NV中心的生产及其在合成钻石(WP3)中的自旋特性。这将与生产人造钻石Element6的世界工业领先者合作完成。将对WP1进行纳米分辨率的单N杂质工程注入，并为WP1和WP2准备合适的浓度。将为这两个WPS开发样品处理，以最大限度地减少导致退相干的不需要的缺陷。还将开发创新的制造技术，例如在单轴应力下优先对准NV中心，这是一种吸引人的可能性。

The aim of QINVC is to exploit the superior quantum coherence of the spins of the negatively charged Nitrogen-Vacancy (NV) colour centres in diamond, at both room and low temperature, for quantum information processing (QIP). This system is indeed among the best solid-state quantum systems in terms of coherence, ease of manipulation by ESR, and addressability down to the single spin using optical microscopy. Our project first focuses on two hybrid strategies for QIP (WP1). The first one consists in fabricating regular arrays of single NV centres, with gate operation performed using a movable NV spin placed at the apex of a cantilever, coming close enough to get entangled with a NV spin on the lattice using magnetic dipolar interaction. The fabrication method is based on pulsed ion beam implantation through a tiny hole threading the tip of an AFM cantilever, or through the voids of a mask deposited at the surface of the diamond sample. The second strategy implements a hybrid architecture for QIP based on circuit QED and ensembles of NV spins: transmon qubits are coupled to ensembles of NV spins through the resonator in which they are embedded. The NV spins will be used as a long-coherence time quantum memory for the transmon qubits which will be used to process quantum information.QINVC will investigate in WP2 the optical properties of NV centres at low temperature. The first goal of WP2 is to transfer the optical techniques used at room temperature to control electron and nuclear spins to low-temperatures, in the purpose of applying them to hybrid quantum circuits (WP1). A second goal is to investigate the potential of NV centres ensembles to build a quantum memory for optical photons. These ambitious goals will request the optimisation of NV centre production and their spin properties in synthetic diamond (WP3) using state-of-the-art methods and beyond. This will be done in collaboration with the world industrial leader on the production of synthetic diamond Element6 Ltd. Engineered implantation of single N impurities with nanometer resolution will be performed for WP1, and suitable concentrations will be prepared for both WP1 and WP2. Sample processing will be developed for these two WPs in order to minimize the unwanted defects that cause decoherence. Innovative fabrication techniques will be also developed, such as the preferential alignment of NV centres under uniaxial stress, an appealing possibility.