In the last decade, proof of concepts has been given and small-scale demonstrators have been built to show that the quantum devices allow obtaining unprecedented performances in practical applications. For example, dramatic enhancements can be obtained in the speed and computational power of next-generation computers (Quantum computing) using superconducting qubits. Also, disruptive performance improvements can be achieved in advanced imaging, remote sensing, long distance/secure communication (quantum cryptography) or diagnostic techniques using superconducting nanowire single-photon detectors - SNSPDs. The transition from demonstrators to practical scaled-up devices with a large number of elements is still at an early stage and a significant technological leap is required for a real breakthrough in those fields.
The identified challenge in scaling-up the number of elements in quantum circuits, that is virtually identical for superconducting qubits and SNSPDs operating in Radio Frequency regime - RF-SNSPDs -, is represented by efficient multiplexing of these elements since they typically operate at cryogenic temperatures and need multiple connections for control and read-out at microwave frequencies. This makes the electronics complex, costly and difficult to scale beyond 10 to 100 of elements in the commercially available cryostats hampering their use in real-world applications.
Single Flux Quantum (SFQ) electronics can operate at cryogenic temperature with unrivalled high frequency and ultra-low power consumption relying on the peculiar current to voltage relation of their basic element: the Josephson Junctions (JJ). Under proper condition, JJs generates ~2 ps width voltage pulses at repetition frequency above 500 GHz, with unprecedented time accuracy, stability and low power consumption.
SFQ electronics is intrinsically scalable and we propose to use generated SFQ pulses as a source for precise and low noise frequency signals for multiplexed control and read-out of on-chip integrated qubits and RF-SNSPDs arrays. This transformative approach will allow to finally fill the gap in the existing quantum technology for a step-change at the same time in quantum science and advanced sensing applications.
At this aim, we will bring together top UK expertise in nanofabrication and superconducting quantum technology, backed by a strong commitment from the UK world-leading company in SFQ electronics and quantum technologies SeeQC UK. We build on previous work carried out through Innovate UK, Marie Curie, Royal Society and European Research Council funding and make complimentary use of expertise and nanofabrication facilities to significant progress in the development of quantum technology in a 3-years targeted programme.
Thanks to the strategic collaboration with National UK Quantum Technology Hubs, we will carry out joint experiments in quantum computing/simulation (Hub in Quantum computing and simulation - HQCS) and in advanced imaging (QuantIC) applications to show the game-changing nature of developed technology. Also, we will leverage support to engage closely with end-users and stakeholder maximizing the impact of the research project. Potential markets for developed technology will be exploited through the collaboration with QT hubs industry partners' network and with the strategic Industrial partners of this proposal like Kelvin Nanotechnology (KNT), Oxford Quantum Circuits (OQC) and SeeQC UK.
This project is designed to generate high-quality research outputs and to deploy advanced technology in the field of quantum science. The work strongly resonates with the central themes of Horizon 2020 programmes and with the UK strategic research priorities set by Research Councils. The long-term goal is to establish a world-class experimental research programme which will have a powerful cross-disciplinary impact strengthening the UK's leading position in new science and technology to generate societal and economic benefits.

Potential Impact:
Quantum computing has quickly gone in few years from being an interesting niche area of science to an identified field of commercial and strategic importance as witnessed by the number of initiative (e.g. UK Blackett review on Quantum Technology, the German study "Entwicklungsstand Quantencomputer", or the recent NPL report 'Opportunities for superconducting quantum technology in the UK') and National/international programmes (UK EPSRC National Quantum Hubs, The EC Quantum Technologies Flagship program and the National Quantum Initiative Act in the US) to promote its development. Large momentum companies such as IBM, Google and Intel but also SMEs are heavily investing in this technology and predictions put a market value of $50 billion on this sector in 2030 [The Coming Quantum Leap in Computing, Boston Consulting Group, 2018]. There are also worldwide scientific programmes on quantum imaging/sensing, as witnessed by recents calls for project funding: US - 2016 DARPA fundamental limits of photon detection programme (DETECT) ($10M), UK - 2015 EPSRC Quantum Imaging Hubs Quantic (£29M) (renewed in 2019), and EU - 2018-2021 Photonics 21 (~ £30M).
The first ramp-up phase of "quantum era" is therefore running but the proceeding beyond its goals will require a disruptive technology step-up that is the real target of this project: We will accelerate the required scale-up step of QT at the same time in computing and sensing to foster the fruition in real-world applications and exploit the "quantum supremacy" across a wide range of disciplines. As consequence, the success of this project has enormous potential to strengthen the UK's leading position in terms of cutting-edge science, strategic scientific capability and advanced technology development leading to commercial opportunities for a huge economic and societal impact.
Technology demonstration, networking and results dissemination:
The project leverages a range of collaborations to deploy the outcome technology directly in advanced applications and highlight its potential and provide impetus towards commercialisation. UK National QT hubs (QuantIC and HQCS) will offer access to public events providing networking and knowledge exchange opportunities across the broad research community to facilitate collaborations (see QuantIC and HQCS LoS). An effective communication strategy including presentations at international conferences, publications of high-profile journal papers and preparation of press releases will be pursued to further enhance the value and impact of the base research.
Industrial engagement and Economical impact:
Access to QT hubs network of industrial partners will trigger joint proposals with stakeholders to get access to Partnership Resource Fund for proof-of-concept (see QuantIC and HQCS LoS) or for commercialisation of outcome technology trough Innovate UK (IUK), Scottish Enterprise and the UK Electronics, Sensors and Photonics Knowledge Transfer Network (ESP KTN) funds. Evaluation of commercialisation mechanism, patenting opportunities and future market creation will be exploited through the support of the strategic partners Oxford Quantum Circuits (OQC), a spin-out company of University of Oxford, and Kelvin Nanotechnology (KNT) Ltd, a spin-out company of UofG (See OQC and KNT LoS). Identified potential customers (e.g. ID Quantic (CH), Leonardo (UK), Single Quantum BV (NL)) expressed their interest in commercialising an end-to-end quantum imaging system.
Societal impact:
Public engagement activities will be organised to raise public awareness on the importance of this disruptive technology for a broad range of applications and inspire the next generation of young scientists and engineers. A strategy will be devised in tandem with the Officer of QT hubs and UofG to maximise the effectiveness of the communication by choosing the events, by providing support for the preparation of dissemination material (presentation, exhibit) and evaluation of the success.