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.

The problem: Building climate change resilience necessarily means building urban resilience. Africa's future is dominated by a rapidly increasing urban population with complicated demographic, economic, political, spatial and infrastructural transitions. This creates complex climate vulnerabilities of critical consequence in the co-dependent city-regions. Climate change substantially complicates the trajectories of African development, exacerbated by climate information that is poorly attuned to the needs of African decision makers. Critical gaps are how climate processes interact at the temporal and spatial scales that matter for decision making, limited institutional capacity to develop and then act on climate information, and inadequate means, methods, and structures to bridge the divides. Current modalities in climate services are largely supply driven and rarely begin with the multiplicity of climate sensitive development challenges. There is a dominant need to address this disconnect at the urban scale, yet climate research in Africa is poorly configured to respond, and the spatial scale and thematic foci are not well attuned to urban problems. Most climate-related policies and development strategies focus at the national scale and are sectorally based, resulting in a poor fit to the vital urban environments with their tightly interlocking place-based systems. Response: FRACTAL's aim is to advance scientific knowledge about regional climate responses to anthropogenic forcings, enhance the integration of this knowledge into decision making at the co-dependent city-region scale, and thus enable responsible development pathways. We focus on city-region scales of climate information and decision making. Informed by the literature, guided by co-exploration with decision makers, we concentrate on two key cross-cutting issues: Water and Energy, and secondarily their influence on food security. We work within and across disciplinary boundaries (transdisciplinarity) and develop all aspects of the research process in collaboration with user groups (co-exploration).The project functions through three interconnected work packages focused on three Tier 1 cities (Windhoek, Maputo and Lusaka), a secondary focus on three Tier 2 cities (Blantyre, Gaborone and Harare), and two self-funded partner cities (Cape Town and eThekwini). Work Package 1 (WP1) is an ongoing and sustained activity operating as a learning laboratory for pilot studies to link research from WP2 and 3 to a real world iterative dialogue and decision process. WP1 frames, informs, and steers the research questions of WP2 and 3, and so centres all research on needs for responsible development pathways of city-region systems. WP2 addresses the decision making space in cities; the political, economic, technical and social determinants of decision making, and seeks to understand the opportunities for better incorporation of climate information into local decision making contexts. WP3, the majority effort, focuses on advancing understanding of the physical climate processes that govern the regional system, both as observed and simulated. This knowledge grounds the development of robust and scale relevant climate information, and the related analysis and communication. This is steered explicitly by WP1's perspective of urban climate change risk, resilience, impacts, and decisions for adaptation and development. The project will frame a new paradigm for user-informed, knowledge-based decisions to develop pathways to resilience for the majority population. It will provide a step change in understanding the cross-scale climate processes that drive change and so enable enhanced uptake of climate information in near to medium-term decision making. The project legacy will include improved scientific capacity and collaboration, provide transferable knowledge to enhance decision making on the African continent, and in this make significant contribution to academic disciplines.

Background: The Problem With the current state of the art, it is possible to limit the access privileges of a third-party program running on a computer system. The addition of architectural capabilities such as provided by CHERI enable unprecedented fine-grained memory protection and isolation. These mechanisms are however not sufficient to control the behaviour of a program so that it follows the intended specification. For example, if a program performs network access, it is not possible to ensure that the network location accessed is intended by the developer, or the result of a backdoor in the system. In general, this is the case for any system call performed by the program. As a result, malicious programs can e.g. participate in DDoS attacks, or send information about the system to a Command and Control server, etc. It is also the case for library calls, which could perform unspecified actions within the memory space of a process. Project Aim The aim of this project is to enhance the provision of Digital Security By Design for mission-critical Systems-on-Chip through Capability hardware-enabled Design-by-Specification. What this means is that the Systems-on-Chip has a formal, executable specification (typically created by the system architect), and every software component of the SoC is forced to adhere to this specification. Programs with incompatible specifications cannot run; unspecified run-time behaviour will raise an exception. For the above example, the specification could govern the network access and also the access to system information. The practical realisation of this aim is through the extension of programming languages to supports expressive specifications and a toolchain which ensures that the specifications are enforced at run time on Capability hardware. Key Ideas in a Nutshell Our vision of how to achieve this goal is through the use of behavioural type systems, i.e. the specification of the SoC and each of its individual components are expressed as a type, which effectively and formally describes the allowed interfaces and interactions of each component. This type-based specification will be an integral component of the program executable, and be validated against an overall system specification by the operating system. This proposal focuses on software components, and will build on the capability hardware for enforcement of the type-based specifications. The type-based Design-by-Specification of hardware components is the topic of the EPSRC Border Patrol project (EP/N028201/1), which will run until 2023 and therefore present great potential for synergies with the current proposal. Prior Work In our current EPSRC project Border Patrol (EP/N028201/1) we investigate digital security by design for the design of hardware IP-core based SoCs. The key mechanism is the use of type-driven design-by-specification. A design's specification is encoded in the type system, so that the implementation must follow the specification. Adherence to the spec can be enforced at design time for trusted modules, and at run time for untrusted modules by patrolling the untrusted module's borders with FSM-based run-time type checkers.

Ice clouds have an important role in the atmosphere, influencing radiative transfer and precipitation formation. The global climatic impact of all clouds types is estimated as a cooling effect. This net cooling effect results from the opposing impacts from liquid clouds (which cool by reflecting sunlight back into space) and ice clouds (which warm through a "greenhouse" effect). Unfortunately there is a lack of understanding of many of the physical processes occurring in ice clouds due to the complexity of ice particle processes and interactions between atmospheric motions, water vapour, and aerosol particles. This means ice clouds are a source of significant uncertainty in climate simulations, and can lead to errors in weather forecasts. Establishing which models are the most accurate remains difficult due to the lack of observations of ice cloud properties. Remote sensing techniques (e.g. radar) can provide observations of ice clouds over large areas on a continuous basis, making them ideal for assessing model skill. However, these techniques do not typically directly measure the atmospherically relevant quantity (e.g. mass of condensed water in a volume of air), and a retrieval must be used to obtain comparable data. These retrievals must invoke several assumptions about the properties of the ice clouds, properties which in reality are highly uncertain. We propose a project to collect a new dataset using in-situ observations from a research aircraft to directly observed ice cloud properties. At the same time, three different radars operating at difference wavelengths will scan the same clouds to allow a variety of radar retrievals to be developed and evaluated. We will obtain data during overpasses from a variety of different satellites which observe ice clouds from space. This work will improve fundamental understanding of ice cloud properties, and lead to improved remote sensing retrievals, both of which will lead to improved model accuracy and reduced uncertainty.

Depletion of stratospheric ozone allows larger doses of harmful solar ultraviolet (UV) radiation to reach the surface leading to increases in skin cancer and cataracts in humans and other impacts, such as crop damage. Ozone also affects the Earth's radiation balance and, in particular, ozone depletion in the lower stratosphere (LS) exerts an important climate forcing. While most long-lived ozone-depleting substances (ODSs, e.g. chlorofluorocarbons, CFCs) are now controlled by the United Nations Montreal Protocol and their abundances are slowly declining, there remains significant uncertainty surrounding the rate of ozone layer recovery. Although signs of recovery have been detected in the upper stratosphere and the Antarctic, this is not the case for the lower stratosphere at middle and low latitudes. In fact, contrary to expectations, ozone in this extrapolar lower stratosphere has continued to decrease (by up to 5% since 1998). The reason(s) for this are not known, but suggested causes include changes in atmospheric dynamics or the increasing abundance of short-lived reactive iodine and chlorine species. We will investigate the causes of this ongoing depletion using comprehensive modelling studies and new targeted observations of the short-lived chlorine substances in the lower stratosphere. While the Montreal Protocol has controlled the production of long-lived ODSs, this is not the case for halogenated very short-lived substances (VSLS, lifetimes <6 months), based on the belief that they would not be abundant or persistent enough to have an impact. Recent observations suggest otherwise, with notable increases in the atmospheric abundance of several gases (CH2Cl2, CHCl3), due largely to growth in emissions from Asia. A major US aircraft campaign based in Japan in summer 2021 will provide important new information on how these emissions of short-lived species reach the stratosphere via the Asian Summer Monsoon (ASM). UEA will supplement the ACCLIP campaign by making targeted surface observations in Taiwan and Malaysia which will help to constrain chlorine emissions. The observations will be combined with detailed and comprehensive 3-D modelling studies at Leeds and Lancaster, who have world-leading expertise and tools for the study of atmospheric chlorine and iodine. The modelling will use an off-line chemical transport model (CTM), ideal for interpreting observations, and a coupled chemistry-climate model (CCM) which is needed to study chemical-dynamical feedbacks and for future projections. Novel observations on how gases are affected by gravitational separation will be used to test the modelled descriptions of variations in atmospheric circulation. The CTM will also be used in an 'inverse' mode to trace back the observations of anthropogenic VSLS to their geographical source regions. The models will be used to quantify the flux of short-lived chlorine and iodine species to the stratosphere and to determine their impact on lower stratospheric ozone trends. The impact of dynamical variability will be quantified using the CTM and the drivers of this determined using the CCM. The model results will be analysed using the same statistical models used to derive the decreasing trend in ozone from observations, including the Dynamical Linear Model (DLM). Overall, the results of the model experiments will be synthesised into an understanding of the ongoing decrease in lower stratospheric ozone. This information will then be used to make improved future projections of how ozone will evolve, which will feed through to the policy-making process (Montreal Protocol) with the collaboration of expert partners. The results of the project will provide important information for future international assessments e.g. WMO/UNEP and IPCC reports.