The description of the laws of quantum mechanics saw a transformation in society's understanding of the physical world-for the first time we understood the rules that govern the counterintuitive domain of the very small. Rather than being just passive observers now scientists are using these laws to their advantage and quantum phenomena are providing us with methods of improved measurement and communication; furthermore they promise a revolution in the way materials are simulated and computations are performed. Over the last decade significant progress has been made in the application of quantum phenomena to meeting these challenges. This "Engineering Photonic Quantum Technologies" Programme Grant goes significantly beyond previous achievements in the quantum technology field. Through a series of carefully orchestrated work packages that develop the underlying materials, systems engineering, and theory we will develop the knowledge and skills that enable us to create application demonstrators with significant academic and societal benefit. For the first time in quantum technologies we are combining materials and device development and experimental work with the important theoretical considerations of architectures and fault tolerant approaches. Our team of investigators and partners have the requisite expertise in materials, individual components, their integration, and the underpinning theory that dictates the optimal path to achieving the programme goals in the presence of real-world constraints. Through this programme we will adopt the materials systems most capable of providing application specific solutions in each of four technology demonstrations focused on quantum communications, quantum enhanced sensing, the construction of a multiplexed single-photon source and information processing systems that outperform modern classical analogues. To achieve this, our underlying technology packages will demonstrate very low optical-loss waveguides which will be used to create the necessary 'toolbox' of photonic components such as splitters, delays, filters and switches. We will integrate these devices with superconducting and semiconducting single-photon detector systems and heralded single-photon sources to create an integrated source+circuit+detector capability that becomes the basis for our technology demonstrations. We address the challenge of integrating these optical elements (in the necessary low-temperature environment) with the very low latency classical electronic control systems that are required of detection-and-feedforward schemes such as multiplexed photon-sources and cluster-state generation and computation. At all times a thorough analysis of the performance of all these elements informs our work on error modelling and fault tolerant designs; these then inform all aspects of the technology demonstrators from inception, through decisions on the optimal materials choices for a system, to the layout of a circuit on a wafer. With these capabilities we will usher in a disruptive transformation in ICT. We will demonstrate mutli-node quantum key distribution (QKD) networks, high-bit rate QKD systems with repeaters capable of spanning unlimited distances. Our quantum enhanced sensing will surpass the classical shot noise limit and see the demonstration of portable quantum-enhanced spectroscopy system. And our quantum information processors will operate with 10-qubits in a fault tolerant scheme which will provide the roadmap to 1,000 qubit cluster state computing architectures.

We aim to grow the world's leading centre for training in quantum engineering for the emerging quantum technology (QT) industry. We have designed this CDT in collaboration with a large number of academic and industry experts, and included as partners those who will add substantially to the training and cohort experience. Through this process a consistent picture of what industry wants in future quantum engineers emerged: people who can tackle the hardest intellectual challenges, recognising the end goal of their research, with an ability to move from fundamental physics towards the challenges of engineering and miniaturising practical systems, who understands the capabilities of other people (and why they are useful). Industry wants people with good decision-making, communication and management skills, with the ability to work across discipline boundaries (to a deadline and a budget!) and build interdisciplinary teams, with the ability to translate a problem from one domain to another. Relevant work experience, knowledge of entrepreneurship, industrial R&D operations and business practices are essential. By forming a hub of unrivalled international excellence in quantum information and photonics, surrounded by world-class expertise in all areas of underpinning science and technology and the scientific and technological application areas of QT, and a breadth of academic and industry partners, we will deliver a new type of training: quantum engineering. Bristol has exceptional international activity in the areas that surround the hub: from microelectronics and high performance computing to system engineering and quantum chemistry. The programme will be delivered in an innovative way-focussing particularly on cohort learning-and assessed by a variety of different means, some already in existence in Bristol. We believe that we are attempting something new and exciting that has the potential to attract and train the best students to ensure that the resulting capacity is world-class, thus providing real benefits to the UK economy.