1,545 research outputs found

    Families of pure PEPS with efficiently simulatable local hidden variable models for most measurements

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    An important problem in quantum information theory is to understand what makes entangled quantum systems non-local or hard to simulate efficiently. In this work we consider situations in which various parties have access to a restricted set of measurements on their particles, and construct entangled quantum states that are essentially classical for those measurements. In particular, given any set of local measurements on a large enough Hilbert space whose dual strictly contains (i.e. contains an open neighborhood of) a pure state, we use the PEPS formalism and ideas from generalized probabilistic theories to construct pure multiparty entangled states that have (a) local hidden variable models, and (b) can be efficiently simulated classically. We believe that the examples we construct cannot be efficiently classically simulated using previous techniques. Without the restriction on the measurements, the states that we construct are non-local, and in some proof-of-principle cases are universal for measurement based quantum computation.This work was supported by EPSRC grant EP/K022512/1.This work was supported by EPSRC grant EP/K022512/1

    Quantum steering ellipsoids, extremal physical states and monogamy

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    A Corrigendum for this article has been published in 2015 New J. Phys. 17 019501Any two-qubit state can be faithfully represented by a steering ellipsoid inside the Bloch sphere, but not every ellipsoid inside the Bloch sphere corresponds to a two-qubit state. We give necessary and sufficient conditions for when the geometric data describe a physical state and investigate maximal volume ellipsoids lying on the physical-unphysical boundary. We derive monogamy relations for steering that are strictly stronger than the Coffman-Kundu- Wootters (CKW) inequality for monogamy of concurrence. The CKW result is thus found to follow from the simple perspective of steering ellipsoid geometry. Remarkably, we can also use steering ellipsoids to derive non-trivial results in classical Euclidean geometry, extending Eulers inequality for the circumradius and inradius of a triangle.The EPSRC and the ARC Centre of Excellence grant no. CE110001027. DJ is funded by the Royal Society. TR would like to thank the Leverhulme Trust. SJ acknowledges EPSRC grant EP/ K022512/1

    A measure of majorisation emerging from single-shot statistical mechanics

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    The use of the von Neumann entropy in formulating the laws of thermodynamics has recently been challenged. It is associated with the average work whereas the work guaranteed to be extracted in any single run of an experiment is the more interesting quantity in general. We show that an expression that quantifies majorisation determines the optimal guaranteed work. We argue it should therefore be the central quantity of statistical mechanics, rather than the von Neumann entropy. In the limit of many identical and independent subsystems (asymptotic i.i.d) the von Neumann entropy expressions are recovered but in the non-equilbrium regime the optimal guaranteed work can be radically different to the optimal average. Moreover our measure of majorisation governs which evolutions can be realized via thermal interactions, whereas the nondecrease of the von Neumann entropy is not sufficiently restrictive. Our results are inspired by single-shot information theory.Comment: 54 pages (15+39), 9 figures. Changed title / changed presentation, same main results / added minor result on pure bipartite state entanglement (appendix G) / near to published versio

    Workshop: The city of proximity: Accessible, Inclusive, Sustainable, Healthy and Salutogenic

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    According to the ‘‘Urban Health Rome Declaration’’ at European meeting ‘‘G7 Health’’ that defines the strategic aspects and actions to improve Urban, Environmental and Public Mental Health into the cities, and referring to the Agenda 2030 in which the 11th SDG argue about ‘‘Sustainable Cities and Communities. Make cities and human settlements inclusive, safe, resilient and sustainable’’, one of the most expressive syntheses of the challenging relationship between urban planning and Public Health is stated by WHO (2016): ‘‘Health is the precondition of urban sustainable development and the first priority for urban planners’’. Referring to the Healthy Cities & Urban Health definitions, we can consider Public Health not merely an aspect of individual health protection and promotion, but a collective condition, strongly influenced by the environmental context and by the strategies implemented by local Governments. The ‘‘Health in All Policies’’ strategy, clearly underlines how health depend by the quality of outdoor and indoor living environments. In this scenario, healthy living and the requirements for healthy places, infrastructure for the public good and Public Health, cycling, walking, disintegrating the role of polluting traffic from the urban environments, social vulnerability and equality are just a few aspects in complex puzzle when designing the urban spaces for healthy, active, walkable cities. The lockdown due to the pandemic has prevented travels, forcing many people to work at home and reducing the possibility of accessing services in the territory. This condition has further highlighted the importance of urban living areas capable of satisfying basic needs within a reasonably easy range of accessibility. The concept of the ‘‘15 minutes city’’ is a useful vision to represent the city of proximity, where it is possible to meet the needs for sustainable, fair, quality, and healthy living. This dimension of proximity can be central to formulating strategies to improve the quality of urban life. A place of proximity, therefore not only defined based on the physical characteristics and people’s uses, but also based on the data collected from a public health perspective in which it is also possible to try to test different types of information and build the conditions to suggest suitable policies and projects. Aim of the Workshop - organized by the two EUPHA Section URB+ENV - it would like to be to build the capacity and knowledge between participants about the main topics and urban features capable to have relevant Urban Public and Environmental Health outcomes. Additional scope is to collected case studies and research experiences considered virtuous at the international level, analyzed in detail to highlight the main urban and architectural features of those healthy experiences and the related health outcomes, such as sedentary lifestyle reduction, increase of the attractiveness of places, reduction of air and noise pollution

    Workshop: Urban Green Spaces, Built Environment and Urban - Mental - Environmental Health outcomes

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    Environmental sustainability, especially in an era of growth health inequality, is one of the most important challenges facing Public Health systems around the World. Environmental sustainability is responsibly interacting with the planet to maintain natural resources and not jeopardize the ability for future generations to meet their needs. The SDGs put environmental sustainability at the center of sustainable development. Environmental Health is the branch of Public Health concerning all aspects of the natural and built environment affecting human health. It is targeted towards preventing disease and creating health-supportive environments. It encompasses the assessment and control of those environmental factors that can potentially affect health, such as pollution, poverty and inadequate energy solutions. Urban Health is an intersectoral arena that links both the public health and the urban planning sectors, mainly captured by SDG3 (including Mental health) and SDG11. Both during the first waves of the Covid-19 pandemic period and in contemporary cities, urban environments were stressed; the resilience of our cities were tested, highlighting the strengths and weaknesses of the urban contexts, not always capable to pro-mote and protect the population health status. Urban Green Spaces (UGS) have proved essential role as ‘‘tools’’ to improve Urban Public and Mental Health. Unfortunately, the heterogeneous distribution of UGS inside the contemporary cities, together with the disparity in quality of such spaces, led to some exclusion phenomena. Evidence/experience-based research strongly demonstrated the positive effects on Public Health of the UGS, and for this reason, they are now becoming the strategic and challenging issue of many urban regeneration programs. The importance of UGS as a key infrastructure has generated the necessity of developing new health-centered design criteria able to conform to their new role in urban environments. The augmentation of UGS surface alone, does not necessarily make cities more livable. An increase in area and surfaces does not translate in ease of accessibility from all social groups or from all the cities’ neighborhoods, or not does it give data on the qualities of such areas, like potential for social engagement or Physical Activity. Aim of the Workshop - organized by the three EUPHA Section URB+MEN+ENV - it would like to be to build the capacity and knowledge between participants about the main topics and urban features capable to have relevant Urban Public, Mental and Environmental Health outcomes. Additional scope is to collected case studies and research experiences considered virtuous at the international level, analyzed in detail to highlight the main urban and architectural features of those healthy experiences and the related health outcomes, such as sedentary lifestyle reduction, increase of the attractiveness of places, reduction of air and noise pollution

    Smallest disentangling state spaces for general entangled bipartite quantum states

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    PACS numbers: 03.67.-a, 03.65.-w, 03.65.Ta, 03.65.Ud.Entangled quantum states can be given a separable decomposition if we relax the restriction that the local operators be quantum states. Motivated by the construction of classical simulations and local hidden variable models, we construct `smallest' local sets of operators that achieve this. In other words, given an arbitrary bipartite quantum state we construct convex sets of local operators that allow for a separable decomposition, but that cannot be made smaller while continuing to do so. We then consider two further variants of the problem where the local state spaces are required to contain the local quantum states, and obtain solutions for a variety of cases including a region of pure states around the maximally entangled state. The methods involve calculating certain forms of cross norm. Two of the variants of the problem have a strong relationship to theorems on ensemble decompositions of positive operators, and our results thereby give those theorems an added interpretation. The results generalise those obtained in our previous work on this topic [New J. Phys. 17, 093047 (2015)].EP/K022512/1/Engineering and Physical Sciences Research Counci

    Improvement for detection of microcalcifications through clustering algorithms and artificial neural networks

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    A new method for detecting microcalcifications in regions of interest (ROIs) extracted from digitized mammograms is proposed. The top-hat transform is a technique based on mathematical morphology operations and, in this paper, is used to perform contrast enhancement of the mi-crocalcifications. To improve microcalcification detection, a novel image sub-segmentation approach based on the possibilistic fuzzy c-means algorithm is used. From the original ROIs, window-based features, such as the mean and standard deviation, were extracted; these features were used as an input vector in a classifier. The classifier is based on an artificial neural network to identify patterns belonging to microcalcifications and healthy tissue. Our results show that the proposed method is a good alternative for automatically detecting microcalcifications, because this stage is an important part of early breast cancer detectio

    Comparison of bio-inspired algorithms applied to the coordination of mobile robots considering the energy consumption

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    Many applications, related to autonomous mobile robots, require to explore in an unknown environment searching for static targets, without any a priori information about the environment topology and target locations. Targets in such rescue missions can be fire, mines, human victims, or dangerous material that the robots have to handle. In these scenarios, some cooperation among the robots is required for accomplishing the mission. This paper focuses on the application of different bio-inspired metaheuristics for the coordination of a swarm of mobile robots that have to explore an unknown area in order to rescue and handle cooperatively some distributed targets. This problem is formulated by first defining an optimization model and then considering two sub-problems: exploration and recruiting. Firstly, the environment is incrementally explored by robots using a modified version of ant colony optimization. Then, when a robot detects a target, a recruiting mechanism is carried out to recruit a certain number of robots to deal with the found target together. For this latter purpose, we have proposed and compared three approaches based on three different bio-inspired algorithms (Firefly Algorithm, Particle Swarm Optimization, and Artificial Bee Algorithm). A computational study and extensive simulations have been carried out to assess the behavior of the proposed approaches and to analyze their performance in terms of total energy consumed by the robots to complete the mission. Simulation results indicate that the firefly-based strategy usually provides superior performance and can reduce the wastage of energy, especially in complex scenarios

    Vrste plesni na kukuruznom klipu uskladištenom u koševima na teritoriji opština Vrnjačka Banja i Kruševac

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    Corn cob owned by individual producers is stored on multiple ways: in barns, attics, sheds etc. If corn cob is not dried properly when stord in barns, it represents ideal foundation for field and storage molds.For our examinations we used corn from 20 barns originating from ten plain and mountain villages in Vrnjacka Banja municipality. Mold isolation was performed on saburo ager on temperature of 27oC. Most commonly isolated sorts of mold were: Penicillium sp., Aspergillus ustus, Alternaria tenuis, Yeast, Mucor mucedo, Fusarium roseum, Aspergillus candidus, Trichoderma viride and Aspergillus flavus. Our results show that dominant role was frequently represented by field molds – Alternaria and Fusarium, most common of storage molds were molds from the genus Aspergillus and Penicillium, and most common progressive decay molds were Mucor and Rhisopos. Infection of grain was by rule 100% with rare exeptions.Kukuruzni klip u vlasništvu individualnih proizvođača skladišti se na više načina: u koševima, tavanima, šupama i dr. Ukoliko se kukuruzni klip, nedovoljno osušen, skladišti u koševe on predstavlja idealnu podlogu za razvoj poljskih i skladišnih plesni. Za ispitivanja smo koristili kukuruz iz 20 koševa koji su poreklom iz 10 sela ravničarskog i planinskog predela sa područja opštine Vrnjačka Banja. Izolaciju plesni vršili smo na Saburo agaru na temperaturi od 27°C. Najčešće su izolovane sledeće vrste plesni: Penicillium sp., Aspergillus ustus, Alternaria tenuis, Kvasnice, Mucor mucedo, Fusarium roseum, Aspergillus candidus, Trichoderma viride i Aspergillus flavus. Naši rezultati pokazuju da su dominantnu ulogu u frekvenciji predstavljale plesni s polja- Alternaria i Fusarium, od plesni uskladištenja najučestalije su bile plesni iz roda Aspergillus i Penicillium, a od plesni uznapredovanog kvarenja Mucor i Rhisopus. Infekcija zrna je bila po pravilu 100% sa retkim odstupanjima

    Maximally and minimally correlated states attainable within a closed evolving system

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    The amount of correlation attainable between the components of a quantum system is constrained if the system is closed. We provide some examples, largely from the field of quantum thermodynamics, where knowing the maximal possible variation in correlations is useful. The optimization problem it raises requires us to search for the maximally and minimally correlated states on a unitary orbit, with and without energy conservation. This is fully solvable for the smallest system of two qubits. For larger systems the problem is reduced to a manageable, classical optimization.Comment: 5 pages, 1 figur
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