Flocking, the collective motion displayed by large groups of birds in the absence of an obvious leader, is one of the most spectacular examples of emergent collective behavior in nature and has fascinated inquiring minds for a long time. Flocking, is not only restricted to birds, but can be observed in an extremely wide range of active matter systems - systems composed by "active particles" able to extract and dissipate energy from their surroundings to produce systematic and coherent motion -- as diverse as fish schools, vertebrate herds, bacteria colonies, insect swarms, active macromolecules in living cells and even driven granular matter. While our knowledge of collective motion has greatly advanced in recent years thanks to the study of minimal models of self propelled particles (SPP) and hydrodynamic continuum theories, as well as the development of the first quantitative experiments, little is known concerning the response of moving groups to perturbations, a question of both theoretical interest (fluctuation-response in out-of-equilibrium physics) and of great ethological importance (biological significance of group response, spatio-temporal mechanisms of information propagation in cases of alert). Protection from external threats is thought to be one of the most important factors in the evolution towards collective behavior, and there is indeed evidence that certain collective properties observed in animal groups cannot be understood in the context of unperturbed theories. Experimental observations in starlings, for instance, have revealed that flocks are much more internally correlated, and thus have a more efficient collective response mechanism than expected from standard unperturbed flocking theories. Our working hypothesis, supported by preliminary results in simple spin systems, is that certain properties of collectively moving animal groups can only be understood in terms of the system response to localized, dynamical perturbations. We will characterize the response of flocks to such perturbations, devoting particular attention to the role of information transmission from the boundaries to the bulk of a finite system. We will also address the origin of such perturbations. They may be exogenous, due to environmental stimuli such as attacking predators or the perception of non-homogeneous landscapes. But perturbations may also be endogenous: even in the absence of external stimuli, individuals may suddenly switch their behavioral patterns so that the group sets itself constantly into a state of dynamical excitation, possibly because this behavior enhances collective response when true perturbations strike. We will consider finite perturbations, which induce a nonlinear response in flocks, but also the limit of infinitesimal perturbations, which may allow for a deeper theoretical analysis of linear response by extension of the fluctuation-dissipation relation (FDR) to flocking systems (out-of-equilibrium generalization of the FDR are already known, but flocking systems remain largely unexplored). This is an issue of great interest for the study of animal group behavior, since it could provide relevant information (at least at the linear level) concerning the response to perturbations starting only from the knowledge of unperturbed fluctuations. It is our goal to extend and test a generalized FDR to flocking systems. This project aims at a well-defined advance in the scientific knowledge and will have direct impact on the academic communities of out-of-equilibrium statistical mechanics and group animal behavior. On a longer time scale, however, a better understanding of emergent collective phenomena in living matter could beneficially impact a number of important fields ranging from biotechnologies (subcellular dynamics of protein filaments, swarming nanorobots) to environmental resources conservation and management (animal group behavior, animal populations response to environmental changes).

Our planet is undergoing unprecedented environmental change and there is an urgent need to understand how species respond to altered abiotic conditions. Development of new technologies has recently seen a revolution in Biology with the advent of tools that enable us to quantify how organisms respond to environmental change at the level of molecules and genes in extremely fine detail. This technological approach to measuring how an organism responds to changes in their environment has become a central theme across Biology. However, technologies for measuring whole-organism level responses have not kept pace, leading to a disconnect between our understanding at these two levels of biological organization. This disconnect is due, in large part, to the challenge of quantifying, in a meaningful way, the complexity and diversity of form and function that is observed at the whole-organism level. The task of quantifying form and function at the whole-organism level is most challenging for organisms during their early development when both form and function are undergoing dynamic transitions. Yet it is at this time when organisms may be most sensitive to environmental stress. Furthermore, the experience of embryos to such stress can have impacts that persist into later life stages, including reproduction. It is therefore important that the effects of environmental stress on early life stages are incorporated into monitoring and prediction of how organisms will respond to forecasted global environmental change. A major objective in our laboratory is to gain a better understanding of how environmental stressors affect the physiology of early life stages of aquatic invertebrates. We have developed a unique bio-imaging capability that allows us to produce high-resolution (temporal and spatial) time lapse video of developing embryos, exposed to tightly controlled environmental conditions. We then extract data from these videos to quantify their physiological function using manual video analysis. Such manual data extraction is time consuming and can be an error-prone and subjective process. Consequently, the process of image analysis forms a major bottleneck in the efficacy and application of this approach to quantification of the responses of large numbers of organisms to environmental change. The main aim of this project is to develop an analytical platform encompassing image analysis pipelines that automate the measurement of a wide range of embryonic features from video. To achieve this we will build image analysis pipelines for measuring functionally relevant traits including growth, gross movement, muscle contraction, heart function, developmental stage and developmental rates. Image analysis pipelines will be embedded within an analytical platform creating a system for organism-wide measurement of different functional traits in individual embryos. Short- and long-term responses of two species (a marine shrimp and freshwater snail) to contrasting temperatures will be used to develop, optimize and validate the analytical framework. The resultant data will enable unrivalled measurement of the responses of developing organisms to factors including environmental stress. This analytical platform would be a powerful tool to any field with an interest in measuring phenotypes in organisms developing in transparent egg capsules e.g. environmental sensitivity measurement, ecotoxicology and drug discovery. Increasing mean global temperatures are threatening both freshwater and marine ecosystems and the use of contrasting temperature will enable assessment of the efficacy of the automated analytical platform in quantifying the sensitivity of early life stages to a current global threat. The analytical resource being developed in this project will facilitate the development of a fully automated capability for measuring the responses and sensitivities of embryonic stages to environmental stress across different aquatic species.

Quantum information science is the field of research that studies the information present in a quantum system. It opens the way to the knowledge of unexplored fundamental physical mechanisms and to the development of novel technologies that will profoundly transform the way we communicate and process our data. Indeed, a number of new technological applications can be envisaged thanks to exquisitely quantum phenomena. While classical information encoding relies on bits, which can be either 0s or 1s, the quantum bits (or qubits) are associated to the state of quantum objects, e.g., single atoms, single spins, or single photons. Because of the quantum superposition principle, the qubits can then be 0s, 1s, or coherent superposition of both, thus giving access to an exceptionally richer alphabet. Quantum information science also exploits quantum entanglement, i.e., strong correlation between quantum objects, as a resource for fast and secure quantum communication protocols. In view of realizing networks for quantum communication, quantum memories are fundamental devices as they act as interfaces between the photons, used as information carriers (or flying qubits), and stationary qubits, exploited for information storage and processing. While atomic gases enabled the first remarkable quantum storage experiments, solid-state systems, and specifically rare earth ion doped crystals, also offer interesting perspectives thanks to the absence of atomic motion and the high density, and the fact that they unleash prospects of integration, which facilitates scalability and employability in real-life quantum technology demonstrations. As a matter of fact, the implementation of quantum information protocols on a small chip has the potential to replicate the revolution of modern electronic miniaturization and intense research efforts are indeed devoted to developing miniaturized photonic integrated circuits for quantum information processing. Yet, on chip memories for single photons, key components of future quantum communication technology, are currently missing. This Fellowship addresses this pressing challenge by developing waveguide quantum memories based on ultrafast laser micromachining of rare earth ion doped crystals. We will engineer the necessary tool kit for the integrated quantum memories to fulfil simultaneously all the requirements for their employability in real-life quantum networks, as on-demand read-out, high efficiency, long storage time, and multimodality. Moreover, we will demonstrate how the integrated design gives access to functionalities that are not possible with bulk devices, like the non-destructive detection of single photons. This vision represents a technological breakthrough toward the realization of complex memory-enhanced quantum photonics circuitry on chip.

Water is the major constituent of cells and must by tightly regulated because its availability affects all biochemical processes. Dynamic cohesive networks of water molecules are disrupted by solutes because water around them can't move freely, forming more structured 'hydration layers' with less potential energy to do work than 'free' water molecules further from the solute. Aqueous solutions therefore reorganise to maximise the potential energy of water. This depends on the solute's concentration and nature: small, charged molecules have less impact on water compared to proteins with large surface areas that may interact unfavourably with water. My team recently found that water behaves very differently in the crowded cellular environment compared to dilute solutions: It becomes very sensitive to small changes in temperature and protein concentration. As temperature falls over the physiological range, more and more water molecules are held in protein hydration layers. This reduces the 'free' water available in cells. Strikingly, we found cells survive extreme cold conditions (0C for 24h) when their growth medium is diluted: Water enters cells by osmosis which restores water balance. Combining two stresses with opposite effects on 'free' water availability prevents cell death and illustrates how critical water's "goldilocks" zone is to life. My team also found new regulatory mechanisms of cellular water balance operating over very short (secs) and longer (hrs) timeframes without any damaging changes in volume. This allows cells to continue functioning efficiently despite natural fluctuations in protein levels, temperature or external salt levels. We also found sequestration of proteins into fluid accumulations called biomolecular condensates (BMCs) releases water molecules from hydration layers, whereas water is recruited to hydration layers when proteins leave BMCs: a rapid feedback mechanisms that adjusts 'free' water availability in cells. This suggests cells may use water to quickly relay signals by altering protein location and activity. Protein levels change over daily cycles and in response to growth signals. Over such timescales, my team found ions move out of cells as protein levels increase and vice versa, facilitated by specific ion transporters. By extension, when membrane channel opening promotes ion efflux in cells, excess 'free' water should leave and cause cells to shrink but they do not. I predict this ion exodus instead drives proteins out of BMCs and other cell compartments to 'soak up' excess water in their hydration layers and this alters protein activity. From these insights, we will answer three questions: 1. Does water acts as a cellular messenger? We will identify water-responsive sensors and how they signal e.g. timing cues to cellular body clocks, immune cell activation, brain cell (astrocyte) activity during learning. 2. Does water regulate inflammation and antiviral defences? Cellular water responds to temperature. We will test how fever directly affects inflammation, which is initiated in response to diverse danger signals but requires ion efflux. I theorise release of BMC components activate vital immune processes. 3. Do viruses exploit water balance to promote replication and transmission? Viruses must minimise disruption to water balance to synthesise their proteins and produce virus before cells die. We will ask how cellular water impacts infection and how viruses manipulate ion transport and BMCs. By answering these questions we will better understand how cells communicate, their immune responses, infection susceptibility and new virus production for disease transmission. My research will inform future interventions to prevent overactivation of inflammation and virus spread. Working out fundamental mechanisms of host cell biology will also provide insight into cell growth and movement, brain signalling, aging and neurodegeneration, and processes like hibernation.

Metamaterials (MMs) are man made materials with unusual electromagnetic properties that are not typically found in Nature. They are the key to achieving such extraordinary properties as invisibility cloaks and perfect lenses. At present, they are bulky and confined to laboratories. If they were flexible, they could become much more versatile and practical. Here, I propose a novel concept for flexible MMs that will turn current cloaking devices from suits of armour into true cloaks.The concept of index of refraction underpins the physics of MMs, which can be illustrated with an example. The direction that light takes when it crosses the interface between two media depends on its initial direction with respect to the surface and on the refractive indices of the media. This is the reason why a pencil appears to kink when immersed in water. In nature, all transparent materials have a positive refractive index, like water. As a result, the image of the pencil always kinks in the same direction. Conversely, MM are manufactured with a negative refractive index, thus in a MM the kink of the pencil would appear in the opposite direction. This effect, which may seem to be a mere curiosity, drives the extraordinary behavior of MMs.The technological requirements of currently fabricated optical MMs impose a flat rigid geometry. This impedes the realistic implementations of an optical cloak made of soft fabric, for example. I aim to overcome such limits.The aim of this project is to fabricate MMs in flexible, extremely thin membranes (METAFLEX).Metaflex will retain all the power of material design typical of MMs and their ability to control light, in a more flexible framework. I have already achieved the first milestone of the project and printed MMs on polymer flexible membranes with thickness down to few nanometers.The physics of Metaflex is a rich and unexplored field of research. This ambitious project is structured around their most striking properties:-Metaflex can be wrapped around objects and stacked, a vital step to realistic cloaking applications.-Metaflex stacks can be easily fine tuned after fabrication, e.g. via deformation, hence light can be controlled with additional degrees of freedom. The flexibility of Metaflex permits the design and fabrication of a camouflaging system, as the material response can sense and adapt to the surrounding environment. This offers a remarkable example of smart fabrics and intelligent textiles, currently a thriving area of research in academia and industry.-Metaflex provide a new framework to study the interaction between optical and mechanical forces, as in Optical Trapping or the new field of Optomechanics. Potential applications include very small optical microphones.-Metaflex are very light. They could take advantage of the attractive and repulsive forces triggered by optical beams in order to levitate and behave as nano-flying carpets. This would be a breakthrough in biomedical nano-applications such as drug-delivery and single molecules manipulation.My interest in Metaflex arises from diverse theoretical and experimental projects in photonic structures and nanofabrication and from the knowledge gained throughout these projects, including the physics and applications of MMs. This project contains many exciting scientific challenges, which offer the possibility of developing the extraordinary properties of MMs for every-day life applications that were unimaginable only a few years ago.