3,558 research outputs found

    Quantum phase space distributions in thermofield dynamics

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    It is shown that the the quantum phase space distributions corresponding to a density operator ρ\rho can be expressed, in thermofield dynamics, as overlaps between the state ρ>\mid \rho > and "thermal" coherent states. The usefulness of this approach is brought out in the context of a master equation describing a nonlinear oscillator for which exact expressions for the quantum phase distributions for an arbitrary initial condition are derived.Comment: 17 pages, revtex, no figures. number of pages were incorrectly stated as 3 instead of 17. No other correction

    Fractional statistic

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    We improve Haldane's formula which gives the number of configurations for NN particles on dd states in a fractional statistic defined by the coupling g=l/mg=l/m. Although nothing is changed in the thermodynamic limit, the new formula makes sense for finite N=pm+rN=pm+r with pp integer and 0<rm.0<r\leq m. A geometrical interpretation of fractional statistic is given in terms of ''composite particles''.Comment: flatex hald.tex, 3 files Submitted to: Phys. Rev.

    Canonical Partition Functions for Parastatistical Systems of any order

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    A general formula for the canonical partition function for a system obeying any statistics based on the permutation group is derived. The formula expresses the canonical partition function in terms of sums of Schur functions. The only hitherto known result due to Suranyi [ Phys. Rev. Lett. {\bf 65}, 2329 (1990)] for parasystems of order two is shown to arise as a special case of our general formula. Our results also yield all the relevant information about the structure of the Fock spaces for parasystems.Comment: 9 pages, No figures, Revte

    Analytic Calculation of Neutrino Mass Eigenvalues

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    Implicaion of the neutrino oscillation search for the neutrino mass square difference and mixing are discussed. We have considered the effective majorana mass m_{ee}, related for \beta\beta_{0\nu}decay. We find limits for neutrino mass eigen value m_{i} in the different neutrino mass spectrum,which explain the different neutrino data.Comment: 10 page

    Wigner function evolution in self-Kerr Medium derived by Entangled state representation

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    By introducing the thermo entangled state representation, we convert the calculation of Wigner function (WF) of density operator to an overlap between "two pure" states in a two-mode enlarged Fock space. Furthermore, we derive a new WF evolution formula of any initial state in self-Kerr Medium with photon loss and find that the photon number distribution for any initial state is independent of the coupling factor with Kerr Medium, where the number state is not affected by the Kerr nonlinearity and evolves into a density operator of binomial distribution.Comment: 9 pages, 1 figur

    Hantavirus-specific antibodies in rodents and humans living in kuwait

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    Hantaviruses are found in widely scattered areas of the world and are transmitted by inhalation of virus-contaminated aerosols of rodent excreta. The present study was undertaken in Kuwait to investigate the serological evidence for hantavirus infection in rodents and humans. Sera were collected from 283 wild rodents and 183 human subjects (46 Kuwaitis and 137 non-Kuwaitis). The rodent sera were investigated for the presence of antibodies against the Seoul and Puumala strains of the hantaviruses by enzyme-linked immunosorbent assay and immunofluorescence technique using the virus-infected Vero E6 cells. The findings showed the presence of anti-hantavirus antibodies in seven out of the 283 (2.8%) rodents. Antibodies against the Seoul strain were present in six (2.1%) and against the Puumala strain in three (1%) rodents. Further, it was observed that three out of 84 (3.6%) of the Rattus norvegicus and four out of 174 (2.3%) Mus musculus had anti-hantavirus antibodies. Two rodents belonging to species Mus musculus had antibodies against both strains of the hantaviruses. Out of 183 human sera, 13 (7%) were positive for hantavirus antibodies. Among the Kuwaitis 5/46 (11%) and among the non-Kuwaitis 8/137 (6%) were positive for the hantavirus antibodies. Antibodies to both Puumala and Hantaan strains were detected in Kuwaitis as well as in non-Kuwaitis. Although no human case of hantavirus illness has yet been reported in Kuwait, the serological evidence of infection suggests a constant vigil

    First-principles quantum dynamics in interacting Bose gases I: The positive P representation

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    The performance of the positive P phase-space representation for exact many-body quantum dynamics is investigated. Gases of interacting bosons are considered, where the full quantum equations to simulate are of a Gross-Pitaevskii form with added Gaussian noise. This method gives tractable simulations of many-body systems because the number of variables scales linearly with the spatial lattice size. An expression for the useful simulation time is obtained, and checked in numerical simulations. The dynamics of first-, second- and third-order spatial correlations are calculated for a uniform interacting 1D Bose gas subjected to a change in scattering length. Propagation of correlations is seen. A comparison is made to other recent methods. The positive P method is particularly well suited to open systems as no conservation laws are hard-wired into the calculation. It also differs from most other recent approaches in that there is no truncation of any kind.Comment: 21 pages, 7 figures, 2 tables, IOP styl

    Exactly solvable models of supersymmetric quantum mechanics and connection to spectrum generating algebra

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    For nonrelativistic Hamiltonians which are shape invariant, analytic expressions for the eigenvalues and eigenvectors can be derived using the well known method of supersymmetric quantum mechanics. Most of these Hamiltonians also possess spectrum generating algebras and are hence solvable by an independent group theoretic method. In this paper, we demonstrate the equivalence of the two methods of solution by developing an algebraic framework for shape invariant Hamiltonians with a general change of parameters, which involves nonlinear extensions of Lie algebras.Comment: 12 pages, 2 figure

    Basic tasks of sentiment analysis

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    Subjectivity detection is the task of identifying objective and subjective sentences. Objective sentences are those which do not exhibit any sentiment. So, it is desired for a sentiment analysis engine to find and separate the objective sentences for further analysis, e.g., polarity detection. In subjective sentences, opinions can often be expressed on one or multiple topics. Aspect extraction is a subtask of sentiment analysis that consists in identifying opinion targets in opinionated text, i.e., in detecting the specific aspects of a product or service the opinion holder is either praising or complaining about

    New Food Technologies in Europe, India and China

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    The use of technology and innovation in developing long-term global food security, and ensuring sustainable and adequate food production, is contextualized by values and controversies associated with food technologies. The framing and context of these technologies may impact on consumer perceptions and acceptance. In some countries this can influence policy decisions. Analysis of the public discourses on the themes of innovation, risk, power and control, and their socio-economic and ethical implications, is applied to explain the utility of novel and emerging food technologies. Potential differences in stakeholder interests are taken into account in different economic and regulatory environments, contrasting Europe with the emerging economies of China and India. In the case of India, there is considerable public debate on finding a balance between various technological choices for food production, viz transgenic, traditional breeding and organic production. In China, the debate about technological innovation is driven largely by political and scientific elites with relatively little consumer debate. European agri-technological innovation is framed by ‘post-productivism’, which informs both implementation strategies and regulatory and governance issues. Economic values cannot be dismissed as irrelevant to the European innovation process, in particular in relation to investment and scientific endeavour
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