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.

This Hub accelerates progress towards a new "quantum era" by engineering small, high precision quantum systems, and linking them into a network to create the world's first truly scalable quantum computing engine. This new computing platform will harness quantum effects to achieve tasks that are currently impossible. The Hub is an Oxford-led alliance of nine universities with complementary expertise in quantum technologies including Bath, Cambridge, Edinburgh, Leeds, Strathclyde, Southampton, Sussex and Warwick. We have assembled a network of more than 25 companies (Lockheed-Martin, Raytheon BBN, Google, AMEX), government labs (NPL, DSTL, NIST) and SMEs (PureLiFi, Rohde & Schwarz, Aspen) who are investing resources and manpower. Our ambitious flagship goal is the Q20:20 engine - a network of twenty optically-linked ion-trap processors each containing twenty quantum bits (qubits). This 400 qubit machine will be vastly more powerful than anything that has been achieved to date, but recent progress on three fronts makes it a feasible goal. First, Oxford researchers recently discovered a way to build a quantum computer from precisely-controlled qubits linked with low precision by photons (particles of light). Second, Oxford's ion-trap researchers recently achieved a new world record for precision qubit control with 99.9999% accuracy. Third, we recently showed how to control photonic interference inside small silica chips. We now have an exciting opportunity to combine these advances to create a light-matter hybrid network computer that gets the 'best of both worlds' and overcomes long-standing impracticalities like the ever increasing complexity of matter-only systems, or the immense resource requirements of purely photonic approaches. Engineers and scientists with the hub will work with other hubs and partners from across the globe to achieve this. At present proof-of-principle experiments exist in the lab, and the 'grand challenge' is to develop compact manufacturable devices and components to build the Q20:20 engine (and to make it easy to build more). We have already identified more than 20 spin-offs from this work, ranging from hacker-proof communication systems and ultra-sensitive medical and military sensors to higher resolution imaging systems. Quantum ICT will bring great economic benefits and offer technical solutions to as yet unsolveable problems. Just as today's computers allow jet designers to test the aerodynamics of planes before they are built, a quantum computer will model the properties of materials before they've been made, or design a vital drug without the trial and error process. This is called digital quantum simulation. In fact many problems that are difficult using conventional computing can be enhanced with a 'quantum co-processor'. This is a hugely desirable capability, important across multiple areas of science and technology, so much so that even the prospect of limited quantum capabilities (e.g. D-Wave's device) has raised great excitement. The Q20:20 will be an early form of a verifiable quantum computer, the uncompromised universal machine that can ultimately perform any algorithm and scale to any size; the markets and impacts will be correspondingly far greater. In addition to computing there will be uses in secure communications, so that a 'trusted' internet becomes feasible, in sensing - so that we can measure to new levels of precision, and in new components - for instance new detectors that allow us to collect single photons. The hub will ultimately become a focus for an emerging quantum ICT industry, with trained scientists and engineers available to address the problems in industry and the wider world where quantum techniques will be bringing benefits. It will help form new companies, new markets, and grow the UK's knowledge economy.