68 research outputs found

    Catalytic Conversion Probabilities for Bipartite Pure States

    Full text link
    For two given bipartite-entangled pure states, an expression is obtained for the least upper bound of conversion probabilities using catalysis. The attainability of the upper bound can also be decided if that bound is less than one.Comment: 4 pages; comments appreciated; the article is a modified version of this preprint combined with arXiv:0707.044

    Random quantum channels I: graphical calculus and the Bell state phenomenon

    Full text link
    This paper is the first of a series where we study quantum channels from the random matrix point of view. We develop a graphical tool that allows us to compute the expected moments of the output of a random quantum channel. As an application, we study variations of random matrix models introduced by Hayden \cite{hayden}, and show that their eigenvalues converge almost surely. In particular we obtain for some models sharp improvements on the value of the largest eigenvalue, and this is shown in a further work to have new applications to minimal output entropy inequalities.Comment: Several typos were correcte

    Research on artificial infection to sunflower leaves grown in conditions of the Ezăreni Farm

    Get PDF
    Sunflower is the most imporant oil crop grown in Romania, with wide use in the food and industry sector. The fungus Sclerotinia sclerotiorum (Lib) de Bary, is a class Ascomycetes, order Heliotiales, family Sclerotinacea. The disease causes economic losses in entire world, particulary the culture on sunflower, Helianthus annuus, was the object of research and disease for decades (Gulya et al., 1997). Sclerotinia sclerotiorum (Lib. de Bary) was described in 1837 by Libert and indentified by Fuckel in 1861(Purdy) is the fungus that causes the most damage up to 100% in many cultures(Sackston, 1992). In all temperate climates regions in the world, white rot disease is the most important, because the fungus remains in the ground,for a period of many years, and range of host plants. This fungus attacks various organs of the plant, the root, stem, leaveas, and head root. This fungus is a parasite polifag which attack over 400 plant species belonging to 75 botanical families, of which many species are plants of cultura of a particular importance in agricultura (sunflower, rapeseed, soybeans) (Boland and Hall 1994). For developing hybrids with genetic resistance, we must reduce the loss caused by this pathogen. The objective in this study was to test some sunflower hybrids under Ezăreni farm with resistant pathogen attack

    Random positive operator valued measures

    Get PDF
    We introduce several notions of random positive operator valued measures (POVMs), and we prove that some of them are equivalent. We then study statistical properties of the effect operators for the canonical examples, starting from the limiting eigenvalue distribution. We derive the large system limit for several quantities of interest in quantum information theory, such as the sharpness, the noise content, and the probability range. Finally, we study different compatibility criteria, and we compare them for generic POVMs

    Evidenţa principalilor agenţi patogeni şi dăunători ai viţei de vie şi controlul fitosanitar al acestora în condiţiile climatice ale anului 2019

    Get PDF
    The careful monitoring of vineyards plays a particularly important role in creating forecasts and warnings to help combat the main pathogens and pests. Mainvine diseases such as downy mildew, powdery mildew and gray rot can cause significant production losses if not combated according to well-established phytosanitary programs. On the other hand, their irrational control can lead to the emergence of phytotoxicity phenomena, or forms of resistance to pests. The present paper aims to present the evolution of the main viticultural diseases that appeared in the SCDVV Iaşi vineyards, in the climatic conditions of 2019

    Random graph states, maximal flow and Fuss-Catalan distributions

    Full text link
    For any graph consisting of kk vertices and mm edges we construct an ensemble of random pure quantum states which describe a system composed of 2m2m subsystems. Each edge of the graph represents a bi-partite, maximally entangled state. Each vertex represents a random unitary matrix generated according to the Haar measure, which describes the coupling between subsystems. Dividing all subsystems into two parts, one may study entanglement with respect to this partition. A general technique to derive an expression for the average entanglement entropy of random pure states associated to a given graph is presented. Our technique relies on Weingarten calculus and flow problems. We analyze statistical properties of spectra of such random density matrices and show for which cases they are described by the free Poissonian (Marchenko-Pastur) distribution. We derive a discrete family of generalized, Fuss-Catalan distributions and explicitly construct graphs which lead to ensembles of random states characterized by these novel distributions of eigenvalues.Comment: 37 pages, 24 figure

    Random repeated quantum interactions and random invariant states

    Full text link
    We consider a generalized model of repeated quantum interactions, where a system H\mathcal{H} is interacting in a random way with a sequence of independent quantum systems Kn,n1\mathcal{K}_n, n \geq 1. Two types of randomness are studied in detail. One is provided by considering Haar-distributed unitaries to describe each interaction between H\mathcal{H} and Kn\mathcal{K}_n. The other involves random quantum states describing each copy Kn\mathcal{K}_n. In the limit of a large number of interactions, we present convergence results for the asymptotic state of H\mathcal{H}. This is achieved by studying spectral properties of (random) quantum channels which guarantee the existence of unique invariant states. Finally this allows to introduce a new physically motivated ensemble of random density matrices called the \emph{asymptotic induced ensemble}

    A review of exposure assessment methods for epidemiological studies of health effects related to industrially contaminated sites

    Get PDF
    BACKGROUND: this paper is based upon work from COST Action ICSHNet. Health risks related to living close to industrially contaminated sites (ICSs) are a public concern. Toxicology-based risk assessment of single contaminants is the main approach to assess health risks, but epidemiological studies which investigate the relationships between exposure and health directly in the affected population have contributed important evidence. Limitations in exposure assessment have substantially contributed to uncertainty about associations found in epidemiological studies. OBJECTIVES: to examine exposure assessment methods that have been used in epidemiological studies on ICSs and to provide recommendations for improved exposure assessment in epidemiological studies by comparing exposure assessment methods in epidemiological studies and risk assessments. METHODS: after defining the multi-media framework of exposure related to ICSs, we discussed selected multi-media models applied in Europe. We provided an overview of exposure assessment in 54 epidemiological studies from a systematic review of hazardous waste sites; a systematic review of 41 epidemiological studies on incinerators and 52 additional studies on ICSs and health identified for this review. RESULTS: we identified 10 multi-media models used in Europe primarily for risk assessment. Recent models incorporated estimation of internal biomarker levels. Predictions of the models differ particularly for the routes ‘indoor air inhalation’ and ‘vegetable consumption’. Virtually all of the 54 hazardous waste studies used proximity indicators of exposure, based on municipality or zip code of residence (28 studies) or distance to a contaminated site (25 studies). One study used human biomonitoring. In virtually all epidemiological studies, actual land use was ignored. In the 52 additional studies on contaminated sites, proximity indicators were applied in 39 studies, air pollution dispersion modelling in 6 studies, and human biomonitoring in 9 studies. Exposure assessment in epidemiological studies on incinerators included indicators (presence of source in municipality and distance to the incinerator) and air dispersion modelling. Environmental multi-media modelling methods were not applied in any of the three groups of studies. CONCLUSIONS: recommendations for refined exposure assessment in epidemiological studies included the use of more sophisticated exposure metrics instead of simple proximity indicators where feasible, as distance from a source results in misclassification of exposure as it ignores key determinants of environmental fate and transport, source characteristics, land use, and human consumption behaviour. More validation studies using personal exposure or human biomonitoring are needed to assess misclassification of exposure. Exposure assessment should take more advantage of the detailed multi-media exposure assessment procedures developed for risk assessment. The use of indicators can be substantially improved by linking definition of zones of exposure to existing knowledge of extent of dispersion. Studies should incorporate more often land use and individual behaviour

    Stable oxygen isotopes in Romanian oak tree rings record summer droughts and associated large-scale circulation patterns over Europe

    Get PDF
    We present the first annual oxygen isotope record (1900 – 2016) from the latewood (LW) cellulose of oak trees (Quercus robur) from NW Romania. As expected, the results correlate negatively with summer relative humidity, sunshine duration and precipitation and positively with summer maximum temperature. Spatial correlation analysis reveals a clear signal reflecting drought conditions at a European scale. Interannual variability is influenced by large-scale atmospheric circulation and by surface temperatures in the North Atlantic Ocean and the Mediterranean Sea. There is considerable potential to produce long and well-replicated oak tree ring stable isotope chronologies in Romania which would allow reconstructions of both regional drought and large-scale circulation variability over southern and central Europe
    corecore