The EPSRC Quantum Communications Hub

量子技术(Qt)是一种新的、颠覆性的信息技术，在通信、传感、成像和计算方面可以超过传统的同行。英国已经在Qt的国家计划上投入了大量资金，以开发和利用这些技术，现在正在进一步投资，以刺激英国的新产业，并在Qt部门产生一批适当熟练的技术人员。所有Qt都以某种方式利用光或物质的各种量子属性。我们的工作是在通信领域，基于测量或检测量子光信号不可逆转地干扰它们的基本效应。这种影响是自然界固有的，即使未来技术(量子或常规)得到改进，这种影响也不会消失。传输的量子光信号的基本干扰可以实现安全通信，因为民间截获的信号在不应该的时候(所谓的窃听者)总是会被抓住。这意味着Alice和Bob可以使用量子光信号来建立安全的共享数据或密钥，然后他们可以使用这些数据和密钥进行一系列安全通信和交易-这就是量子密钥分配(QKD)。光的不可逆干扰也可以用来产生随机数，这是安全通信、密码学、模拟和建模的另一个非常重要的组成部分。在通信如此普遍和重要的现代世界，对新的安全方法的需求越来越大。今天广泛使用的技术和方法将容易受到新兴量子计算技术的影响，因此今天发送的加密信息具有较长的安全保质期，未来将面临风险。必须开发新的“量子安全”方法，这种方法不会受到未来任何量子时间的影响。因此，QKD和新的数学加密必须尽快变得实用和经济有效。因此，量子通信中心的宏伟愿景是在所有距离范围内追求量子通信，提供一系列应用和服务，并具有与现有基础设施集成的潜力。极短距离的通信需要自由的空间连接以实现灵活性。例如，在电话或其他手持设备与终端之间，或在许多设备与房间中的固定接收器之间。该中心将设计这些“多对一”技术，以增强实用性和现实操作能力。更远距离的传统通信--在城市、城市和城市间的规模--已经使用了光纤，量子通信必须利用和补充这一点。Hub已经建立了英国第一个量子网络UKQN。我们将扩展和增强UKQN，增加功能和能力，并引入新的QKD技术-使用类似于传统通信中使用的量子光，或使用纠缠致力于更远距离的光纤通信。最远距离的通信--洲际通信和跨洋通信--需要卫星。因此，该中心将致力于一项新的计划，开发地面到卫星的量子密钥分发链路。用于所有距离刻度的商业量子密钥分发技术将需要小型化，以实现尺寸、重量和功率的节省，并实现大规模生产。因此，该中心将致力于芯片上操作和集成的密钥工程。尽管密钥共享广泛适用，但它并不能为所有安全通信场景提供解决方案。因此，Hub将研究其他新的量子协议，并将QKD纳入更广泛的安全解决方案。鉴于世界范围内不断变化的格局，英国在量子通信技术及其关键部件(如光源和探测器)方面建立国家能力变得越来越重要。该中心组建了一支优秀的团队来提供这一能力。

Quantum technologies (QT) are new, disruptive information technologies that can outperform their conventional counterparts, in communications, sensing, imaging and computing. The UK has already invested significantly in a national programme for QT, to develop and exploit these technologies, and is now investing further to stimulate new UK industry and generate a supply of appropriately skilled technologists across the range of QT sectors.All QT exploit the various quantum properties of light or matter in some way. Our work is in the communications sector, and is based on the fundamental effect that measuring or detecting quantum light signals irreversibly disturbs them. This effect is built into Nature, and will not go away even when technologies (quantum or conventional) are improved in the future. The fundamental disturbance of transmitted quantum light signals enables secure communications, as folk intercepting signals when they are not supposed to (so-called eavesdroppers) will always get caught. This means Alice and Bob can use quantum light signals to set up secure shared data, or keys, which they can then use for a range of secure communications and transactions - this is quantum key distribution (QKD). The irreversible disturbance of light can also be used to generate random numbers - another very important ingredient for secure communications, cryptology, simulation and modelling.In the modern world where communications are so ubiquitous and important, there is increasing demand for new secure methods. Technologies and methods widely used today will be vulnerable to emergent quantum computing technologies, so encrypted information being sent around today which has a long security shelf-life will be at risk in the future. New "quantum safe" methods that are not vulnerable to any future QT have to be developed. So QKD and new mathematical encryption must be made practical and cost effective, and soon. The grand vision of the Quantum Communications Hub is therefore to pursue quantum communications at all distance scales, to offer a range of applications and services and the potential for integration with existing infrastructure. Very short distance communications require free space connections for flexibility. Examples include between a phone or other handheld device and a terminal, or between numerous devices and a fixed receiver in a room. The Hub will be engineering these "many-to-one" technologies to enhance practicality and real-world operation. Longer distance conventional communications - at city, metropolitan and inter-city scales - already use optical fibres, and quantum communications have to leverage and complement this. The Hub has already established the UK's first quantum network, the UKQN. We will be extending and enhancing the UKQN, adding function and capability, and introducing new QKD technologies - using quantum light analogous to that used in conventional communications, or using entanglement working towards even longer distance fibre communications. The very longest distance communications - intercontinental and across oceans - require satellites. The Hub will therefore work on a new programme developing ground to satellite QKD links.Commercial QKD technologies for all distance scales will require miniaturisation, for size, weight and power savings, and to enable mass manufacture. The Hub will therefore address key engineering for on-chip operation and integration.Although widely applicable, key-sharing does not provide a solution for all secure communication scenarios. The Hub will therefore research other new quantum protocols, and the incorporation of QKD into wider security solutions.Given the changing landscape worldwide, it is becoming increasingly important for the UK to establish national capability, both in quantum communication technologies and their key components such as light sources and detectors. The Hub has assembled an excellent team to deliver this capability.