o achieve this vision, we will address major global research challenges towards the establishment of the "quantum internet" —?globally interlinked quantum networks which connect quantum nodes via quantum channels co-existing with classical telecom networks. These research challenges include: low-noise quantum memories with long storage time; connecting quantum processors at all distance scales; long-haul and high-rate quantum communication links; large-scale entanglement networks with agile routing capabilities compatible with - and embedded in - classical telecommunicatons networks; cost-effective scalability, standardisation, verification and certification. By delivering technologies and techniques to our industrial innovation partners, the IQN Hub will enable UK academia, national laboratories, industry, and end-users to be at the forefront of the quantum networking revolution. The Hub will utilise experience in the use of photonic entanglement for quantum key distribution (QKD) alongside state-of-the art quantum memory research from existing EPSRC Quantum Technology Hubs and other projects to form a formidable consortium tackling the identified challenges. We will research critical component technology, which will underpin the future national supply chain, and we will make steps towards global QKD and the intercontinental distribution of entanglement via satellites. This will utilise the Hub Network's in-orbit demonstrator due to be launched in late 2024, as well as collaboration with upcoming international missions. With the National Quantum Computing Centre (NQCC), we will explore applications towards quantum advantage demonstrations such as secure access to the quantum cloud, achievable only through entanglement networks. Hub partner National Physical Laboratory (NPL) working with our academic partners and the National Cyber Security Centre (NCSC) will ensure that our efforts are compatible with emerging quantum regulatory standards and post-quantum cybersecurity to bolster national security. We will foster synergies with competing international efforts through healthy exchange with our global partners. The Hub's strong industrial partner base will facilitate knowledge exchange and new venture creation. Achieving the IQN Hub's vision will provide a secure distributed and entanglement-enabled quantum communication infrastructure for UK end-users. Industry, government stakeholders and the public will be able to secure data in transit, in storage and in computation, exploiting unique quantum resources and functionalities. We will use a hybrid approach with existing classical cyber-security standards, including novel emerging post-quantum algorithms as well as hardware security modules. We will showcase our ambition with target use-cases that have emerged as barriers for industry, after years of investigation within the current EPSRC QT Hubs as well as other international efforts. These barriers include security and integrity of: (1) device authentication, identification, attestation, verification; (2) distributed and cloud computing; (3) detection, measurement, sensing, synchronisation. We will demonstrate novel applications as well as identify novel figures of merit (such as resilience, accuracy, sustainability, communication complexity, cost, integrity, etc.) beyond security enhancement alone to ensure the national quantum entanglement network can be fully exploited by our stakeholders and our technology can be rapidly translated into a commercial setting.

Quantum technologies exploit the intriguing properties of matter and light that emerge when the randomizing processes of everyday situations are subdued. Particles then behave like waves and, like the photons in a laser beam, can be split and recombined to show interference, providing sensing mechanisms of exquisite sensitivity and clocks of exceptional accuracy. Quantum measurements affect the systems they measure, and guarantee communication security by destroying cryptographic keys as they are used. The entanglement of different atoms, photons or circuits allows massively powerful computation that promises complex optimizations, ultrafast database searches and elusive mathematical solutions. These quantum technologies, which EPSRC has declared one of its four Mission-Inspired priorities, promise in the near future to stand alongside electronics and laser optics as a major technological resource. In this 'second quantum revolution', a burgeoning quantum technology industry is translating academic research and laboratory prototypes into practical devices. Our commercial partners - global corporations, government agencies, SMEs, start-ups, a recruitment agency and VC fund - have identified a consistent need for hundreds of doctoral graduates who combine deep understanding of quantum science with engineering competence, systems insight and a commercial head. With our partners' guidance, we have designed an exciting programme of taught modules to develop knowledge, skills and awareness beyond the provision of traditional science-focused PhD programmes. While pursuing leading-edge research in quantum science and engineering, graduate students in the EPSRC CDT for Quantum Technology Engineering will follow a mix of lectures, practical assignments and team work, peer learning, workshops, and talks by our commercial partners. They will strengthen their scientific and engineering capabilities, develop their computing and practical workshop skills, study systems engineering and nanofabrication, project and risk management and a range of commercial topics, and receive professional coaching in communication and presentation. An industrial placement and extended study visit will give them experience of the commercial environment and global links in their chosen area, and they will have support and opportunities to break their studies to explore the commercialization of research inventions. A QT Enterprise Club will provide fresh, practical entrepreneurship advice, as well as a forum for local businesses to exchange experience and expertise. The CDT will foster an atmosphere of team working and collaboration, with a variety of group exercises and projects and constant encouragement to learn from and about each other. Students will act as mentors to junior colleagues, and be encouraged to take an active interest in each other's research. They will benefit from the diversity of their peers' backgrounds, across not just academic disciplines but also career stages, with industry secondees and part-time students bringing rich experience and complementary expertise. Students will draw upon the wealth of experience, across all corners of quantum technologies and their underpinning science and techniques, provided by Southampton's departments of Physics & Astronomy, Engineering, Electronics & Computer Science, Chemistry and its Optoelectronics Research Centre. They will be given training and opening credit for the Zepler Institute's nanofabrication facilities, and access to the inertial testing facilities of the Institute of Sound & Vibration research and the trials facilities of the National Oceanography Centre. Our aim is that graduates of the CDT will possess not only a doctorate in the exciting field of quantum technology, but a wealth of knowledge, skills and awareness of the scientific, technical and commercial topics they will need in their future careers to propel quantum technologies to commercial success.

Silicon photonics is the manipulation of light (photons) in silicon-based substrates, analogous to electronics, which is the manipulation of electrons. The development cycle of a silicon photonics device consists of three stages: design, fabrication, and characterisation. Whilst design and characterisation can readily be done by research groups around the country, the fabrication of silicon photonics devices, circuits and systems requires large scale investments and capital equipment such as cleanrooms, lithography, etching equipment etc. Based at the Universities of Southampton and Glasgow, CORNERSTONE 2.5 will provide world-leading fabrication capability to silicon photonics researchers and the wider science community. Whilst silicon photonics is the focus of CORNERSTONE 2.5, it will also support other technologies that utilise similar fabrication processes, such as MEMS or microfluidics, and the integration of light sources with silicon photonics integrated circuits, as well as supporting any research area that requires high-resolution lithography. The new specialised capabilities available to researchers to support emerging applications in silicon photonics are: 1) quantum photonics based on silicon-on-insulator (SOI) wafers; 2) programmable photonics; 3) all-silicon photodetection; 4) high efficiency grating couplers for low energy, power sensitive systems; 5) enhanced sensing platforms; and 6) light source integration to the silicon nitride platform. Access will be facilitated via a multi-project-wafer (MPW) mechanism whereby multiple users' designs will be fabricated in parallel on the same wafer. This is enabled by the 8" wafer-scale processing capability centred around a deep-UV projection lithography scanner installed at the University of Southampton. The value of CORNERSTONE 2.5 to researchers who wish to use it is enhanced by a network of supporting companies, each providing significant expertise and added value to users. Supporting companies include process-design-kit (PDK) software specialists (Luceda Photonics), reticle suppliers (Compugraphics, Photronics), packaging facilities (Tyndall National Institute, Bay Photonics, Alter Technologies), a mass production silicon photonics foundry (CompoundTek), an epitaxy partner for germanium-on-silicon growth (IQE), fabrication processing support (Oxford Instruments), an MPW broker (EUROPRACTICE), a III-V die supplier (Sivers Semiconductors) and promotion and outreach partners (Photonics Leadership Group, EPIC, CSA Catapult, CPI, Anchored In). Access to the new capabilities will be free-of-charge to UK academics in months 13-18 of the project, and 75% subsidised by the grant in months 19-24. During the 2-year project, we will also canvas UK demand for the capability to continue to operate as an EPSRC National Research Facility, and if so, to establish a Statement of Need.