Quantum processors and quantum computers employ principles of quantum mechanics to analyse, process, store and protect information. Therefore, quantum processing and computing, operating using superposition, will revolutionise our conventional way of data processing and computing in speed, power, and security, which will affect our lives, economy, and security in national and international quantities. Superconducting quantum processors on large scale with a number of quantum bits, rather than classical bits, of more than 500, are one of the most promising platforms to realise quantum computers. The quantum state of these processors, commonly known as coherence in superconducting transmons, is fragile to weak environmental perturbations such as imperfection in materials, current noise in the quantum chip, or heat load associated with the transmon qubits control and read-out electronics. In this three years project, our team together with our project partners aim at: (i) developing a new type of qubits that are controlled and addressed by the gate voltage, rather than conventional transmons that are operating based on current flux control lines. Our proposed qubit is known as gatemon and we aim to fabricate them on large scale in a low-loss silicon chip. Each individual gatemon will be shunted by a parallel plate capacitor in a single quantum chip. Our strategy to integrate our gatemons on large scale is to use low-loss two-dimensional materials to build the shunted capacitors. Such technology would allow us to miniaturise the footprint of our gatemon quantum chips by > 2000 times smaller. The gatemon chips will be operated at the 10mK stage of a dilution refrigerator. All fabrication and measurements will take place at the University of Glasgow James Watt Nanofabrication Centre (JWNC), and at the Centre for Quantum Technology. (ii) developing a proof of concept modern electronics that can work at low temperatures, known as cryogenic electronics based on CMOS electronics. The chips will be mounted at the 3K stage of the dilution refrigerator to control and readout the gatemon quantum chips. (iii) training and educating a diverse cohort of next-generation UK quantum technology students, academics, and engineers promoting capability in a research field with significant national and international economic potential and interests but with significant employment shortage. The outputs of the SEQUENCE project will deliver a major breakthrough to quantum computing science and technology, advance low-power and reliable devices for cryoelectronic applications, and allow the technological relevance of our work to be placed on a sound footing in the industrial context.

Quantum computation has just entered a new era, that of Noisy Intermediate-Scale Quantum (NISQ) technologies in which quantum processors are able to perform calculations beyond the capabilities of the world's greatest supercomputers. This remarkable achievement sets an important milestone in quantum computing (QC) and brings focus towards the ultimate goal of the QC roadmap: building a fault-tolerant quantum machine. A machine with sufficient error-free computing resources to run quantum algorithms with the potential to radically transform society. Algorithms that will help us better forecast weather and financial markets, speed up searches in unsorted databases, essential for the Big Data era, and most importantly, accelerate the pace of discovery of new materials and medicines, so relevant for the times we live in. The most promising routes to fault-tolerant QC will require quantum error correction (QEC) to enable accurate computing despite the intrinsically noisy nature of the individual quantum bits constituting the machine. The idea is based on distributing the logical information over a number of physical qubits. As long as the physical qubits satisfy a maximum error rate (1% for the most forgiving method, the surface code) fault-tolerance can be achieved. The exact physical qubit overhead (per logical qubit) depends on the error rate but considering state-of-the-art qubit fidelities, it will likely be a figure in excess of a hundred. QEC is then expected to take the number of required physical qubits to many thousands for economically significant algorithms and to many millions for some of the more demanding quantum computing applications. Scaling is hence a generic scientific and technological challenge. Building qubits based on the spin degree of freedom of individual electrons in silicon nanodevices offers numerous advantages over competing technologies such as the scalability of the most compact solid-state approach and the extensive industrial infrastructure of silicon transistor technology devoted to fabricating multi-billion-element integrated circuits. Besides, silicon electron spin qubits are one of the most coherent systems in nature, characteristic that has enabled demonstrating all the operational steps - initialization, control and readout - with sufficient level of precision for fault-tolerant computing. However, most of the results achieved so far come from devices fabricated in academic cleanrooms with relatively low level of reproducibility and in one- or two-qubit processors at best [Huang et al. Nature 569, 532]. But the recent demonstration of a single hole spin qubit [Maurand et al Nat Commun 7 13575] and electron spin control and readout in devices fabricated in a 300 mm complementary metal-oxide-semiconductor (CMOS) platform open an opportunity to trigger a transition from lab-based proof-of-principle experiments to manufacturing qubits at scale [Gonzalez-Zalba et al, Physics World (2019)]. In the project SiFT, I will build on my pioneering work on CMOS-based quantum computing [Nat Commun 6 6084, Nat Elect 2 236, Nat Nano 14 437] to demonstrate, for the first time, all the necessary steps to run the surface code. I will target a two-dimensional qubit lattices where arbitrary quantum errors could be detected and corrected making clusters of qubits more reliable that the individual constituents. My quantum circuit designs will be manufactured in experimental and commercial silicon foundries that use very large-scale integration processes. The project will be the steppingstone towards building in the UK a large-scale silicon-based quantum processor with sufficient error-free computational resources to make an impact on society. It will help take QC beyond NISQ into the fault-tolerant era where the computational promises of QC can be fully exploited.

The project Software Enabling Early Quantum Advantage (SEEQA, pronounced 'seeker') is a joint effort by Oxford, UCL, and Bristol, supported by multiple UK quantum startup companies and NQCC. The aim is to make the era of "quantum advantage" arrive sooner! "Advantage" means having real working quantum computers that can perform tasks that are either impossible, or prohibitively slow or expensive, by any conventional means. We'll know this era has arrived when we can solve otherwise-infeasible tasks in areas such as chemistry and materials discovery or in solving complicated resource allocation problems with near-zero waste. Although quantum computers have long promised this kind of advantage, it has not yet been realised. There are many reasons -- partly it is just that the prototype hardware needs more time to mature. But progress needs to be made in the practical theory to support quantum computing, to 'lower the bar' that the hardware needs to be able to reach. This is what SEEQA will do, in three main themes: 1. Figuring out how best to use state-of-the-art conventional computing power to help early quantum computers. There are two main ways: First, the conventional computers can actually help run the task that the quantum computer is performing. The task gets broken up into lots of small quantum computations, and the conventional computer gets all the results and puts them together to decide what to do next. The other way a conventional computer can help is by monitoring the quantum processor for errors: there is some detective work to do in order to infer the nature of the errors from the evidence that comes from monitoring, and a conventional computer needs to do this -- it's called decoding. 2. Coming up with new ways in which to handle or suppress errors. As mentioned, quantum computers (especially the early ones) suffer from 'noise' which means little imperfections in everything that is done. If not handled, the resulting errors will lead to useless outputs. There are many ideas for fighting errors, but SEEQA will address new possibilities. In particular, SEEQA will investigate the interface between two major approaches to find new solutions: The approaches are called Quantum Error Mitigation (QEM), which suppresses error damage, and Quantum Error Correction (QEC) which can totally fix errors but is currently very expensive in terms of number of components needed. Also, SEEQA will explore and advance some of the more recent and sophisticated ideas for handling measurement errors -- if you can't trust the output of the quantum computer you are very limited! 3. Finally, SEEQA will focus on the interrelationship between the architecture or protocol we would like to perform, and the available hardware architecture (including noise sources and other imperfections, the 'topology' which means the question of which qubits can directly 'see' other qubits, and so on). Although quite a bit is known about this, there remain a great many questions within the two themes (a) "what algorithms can run well on my architecture?", and (b) "what architectures can my algorithm run on?" Underpinning all this theoretical research, it will be vital to be able to test things out. The SEEQA project will have two kinds of provision: First, very efficient software that runs on conventional computers to 'pretend' to be quantum computers - exactly simulating them using the well-known laws of quantum physics. However it will only ever be possible to work with small emulated quantum computers because the quantum state is so complex. So it is vital that SEEQA also has access to real prototype quantum processors -- and as many as possible because they are various types. Fortunately SEEQA has multiple letters of support, offering resources approaching £500k, from pioneering UK hardware companies that have working quantum prototypes right now. They will make available their experts and their devices to SEEQA in order to help us to succeed.

The primary objective of the QC2 CDT is to train the upcoming generation of pioneering researchers, entrepreneurs, and business leaders who will contribute to positioning the UK as a global leader in the quantum-enabled economy by 2033. The UK government and industry have demonstrated their commitment by investing £1 billion in the National Quantum Technologies Programme (NQTP) since 2014. In its March 2023 National Quantum Strategy document, the UK government reaffirmed its dedication to quantum technologies, pledging £2.5 billion in funding over the next decade. This commitment includes the establishment of the UKRI National Quantum Computing Centre (NQCC). The fields of quantum computation and quantum communications are at a pivotal juncture, as the next decade will determine whether the long-anticipated technological advancements can be realized in practical, commercially-viable applications. With a wide-ranging spectrum of research group activities at UCL, the QC2 CDT is uniquely situated to offer comprehensive training across all levels of the quantum computation and quantum communications system stacks. This encompasses advanced algorithms and quantum error-correcting codes, the full range of qubit hardware platforms, quantum communications, quantum network architectures, and quantum simulation. The QC2 CDT has been co-developed through a partnership between UCL and a network of UK and international partners. This network encompasses major global technology giants such as IBM, Amazon Web Services and Toshiba, as well as leading suppliers of quantum engineering systems like Keysight, Bluefors, Oxford Instruments and Zurich Instruments. We also have end-users of quantum technologies, including BT, Thales, NPL, and NQCC, in addition to a diverse group of UK and international SMEs operating in both quantum hardware (IQM, NuQuantum, Quantum Motion, SeeQC, Pasqal, Oxford Ionics, Universal Quantum, Oxford Quantum Circuits and Quandela) and quantum software (Quantinuum, Phase Craft and River Lane). Our partners will deliver key components of the training programme. Notably, BT will deliver training in quantum comms theory and experiments, IBM will teach quantum programming, and Quantum Motion will lead a training experiment on semiconductor qubits. Furthermore, 17 of our partners will co-sponsor and co-supervise PhD projects in collaboration with UCL academics, ensuring a strong alignment between the research outcomes of the CDT and the critical research objectives of the UK quantum economy. In total the cash and in-kind contributions from our partners exceed £9.1 million, including £2.944 million cash contribution to support 46 co-sponsored PhD studentships. QC2 will provide an extensive cohort-based training programme. Our students will specialize in advanced research topics while maintaining awareness of the overarching system requirements for these technologies. Central to this programme is its commitment to interdisciplinary collaboration, which is evident in the composition of the leadership and supervisory team. This team draws expertise from various UCL departments, including Chemistry, Electronics and Electrical Engineering, Computer Science, and Physics, as well as the London Centre for Nanotechnology (LCN). QC2 will deliver transferable skills training to its students, including written and oral presentation skills, fostering an entrepreneurial mindset, and imparting techniques to maximize the impact of research outcomes. Additionally, the programme is committed to taking into consideration the broader societal implications of the research. This is achieved by promoting best practices in responsible innovation, diversity and inclusion, and environmental impact.

For many years, quantum mechanics has been a curiosity at the heart of physics. Its development was essential to many of the key breakthroughs of 20th century science, but it is famous for counter-intuitive features; the superposition illustrated by Schrödinger's cat; and the quantum entanglement responsible for Einstein's "spooky action at a distance". Quantum Technologies are based on the idea that the "weirdness" of quantum mechanics also presents a technological opportunity. Since quantum mechanical systems behave in a fundamentally different way to large-scale systems, if this behaviour could be controlled and exploited it could be utilised for fundamentally new technologies. Ideas for using quantum effects to enhancing computation, cryptography and sensing emerged in the 1980s, but the level of technology required to exploit them was out of reach. Quantum effects were only observed in systems at either very tiny scales (at the level of atoms and molecules) or very cold temperatures (a fraction of a degree above absolute zero). Many of the key quantum mechanical effects predicted many years ago were only confirmed in the laboratory in the 21st century. For example, a decisive demonstration of Einstein's spooky action at a distance was first achieved in 2015. With such rapid experimental progress in the last decade, we have reached a turning point, and quantum effects previously confined to university laboratories are now being demonstrated in commercially fabricated chips and devices. Quantum Technologies could have a profound impact on our economy and society; Quantum computers that can perform computations beyond the capabilities of the most powerful supercomputer; microscopic sensing devices with unprecedented sensitivity; communications whose security is guaranteed by the laws of physics. These technologies could be hugely transformative, with potential impacts in health-care, finance, defence, aerospace, energy and transport. While the past 30 years of quantum technology research have been largely confined to universities, the delivery of practical quantum technologies over the next 5-10 years will be defined by achievements in industrial labs and industry-academic partnerships. For this industry to develop, it will be essential that there is a workforce who can lead it. This workforce requires skills that no previous industry has utilised, combining a deep understanding of the quantum physics underlying the technologies as well as the engineering, computer science and transferrable skills to exploit them. The aim of our Centre for Doctoral Training is to train the leaders of this new industry. They will be taught advanced technical topics in physics, engineering, and computer science, alongside essential broader skills in communication and entrepreneurship. They will undertake world-class original research leading to a PhD. Throughout their studies they will be trained by, and collaborate with a network of partner organisations including world-leading companies and important national government laboratories. The graduates of our Centre for Doctoral Training will be quantum technologists, helping to create and develop this potentially revolutionary 21st-century industry in the UK.