Spin-photon systems for scalable quantum processors

光学技术是许多通信、测量和传感任务的关键。事实上，光通信（在低损耗光纤中）支撑着全球经济，支持着世界范围内近乎瞬时的太比特级信息传输。然而，尽管20世纪90年代的乐观主义，全光交换和计算并没有得到显著的发展。这主要是因为弱光学非线性导致高功率要求和低开关速度的问题。在本提案中，我将开发一种基于固体主机中原子缺陷耦合的新型光开关技术。该技术有望实现高速低功耗光交换机，可以彻底改变所有光网络的路由和许多其他信号调节任务，在全光领域执行。量子光子技术的最新发展，如量子安全密钥分发和量子计算的愿景，也受到单光子水平上缺乏非线性的限制。缺失的组件实际上是一个确定性纠缠器，能够在单独的光子之间或量子比特的单独固态实现之间诱导强相关性。本项目旨在基于我们早期发明的自旋光子纠缠器开发这样的门，该纠缠器使用单电荷量子点或色心与微腔强耦合。事实证明，该元件是量子计算的通用门，该门的实验实现是这里的关键目标。一旦这样的组件可用，它将为远程“量子互联网”铺平道路，并为可扩展量子计算机技术的发展铺平道路，从而实现基于电路和测量的量子计算。最终目标是开发一种解决经典和量子应用的技术，使用嵌入波长尺度光学腔（或波导）中的单原子状光发射器，配置为阿焦耳光开关或高保真高效自旋光子纠缠门。

Optical technologies are key to many communications, measurement and sensing tasks. In fact optical communication (in low loss fibres) underpins the global economy, supporting the near instantaneous transmission of terabits of information worldwide. However all-optical switching and computing have not developed dramatically despite optimism in the 1990's. This is primarily because of the problem of weak optical nonlinearity leading to high power requirements and low switching speeds. In this proposal I will develop a new optical switching technology based on the coupling of atom like defects in solid state hosts. The technology promises a high speed low power optical switch which could revolutionise all optical networks with routing and many other signal conditioning tasks performed in the all-optical domain. The more recent developments of quantum photonic technologies such as quantum secured key distribution and the vision of quantum computing are also limited by the lack of a non-linearity at the single photon level. The missing component is in fact a deterministic entangler capable of inducing strong correlations between separate photons or between separate solid state realisations of quantum bits. This project aims to develop such gates based on our earlier invention a spin photon entangler which uses a singly charged quantum dot or colour centre strongly coupled to a microcavity. It turns out this element is a universal gate for quantum computation and experimental realisation of this gate is a key target here. Once such a component is available it will pave the way to a long range 'quantum internet' and to the development of a scalable quantum computer technology allowing both circuit and measurement based quantum computing realisations to be envisaged. The end goal is to develop a technology that addresses both classical and quantum applications using single atom-like light emitters embedded in wavelength scale optical cavities (or waveguides) configured as either attojoule optical switches or high-fidelity efficient spin-photon entangling gates.