3,558 research outputs found
Quantum phase space distributions in thermofield dynamics
It is shown that the the quantum phase space distributions corresponding to a
density operator can be expressed, in thermofield dynamics, as overlaps
between the state 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
We improve Haldane's formula which gives the number of configurations for
particles on states in a fractional statistic defined by the coupling
. Although nothing is changed in the thermodynamic limit, the new
formula makes sense for finite with integer and 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
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
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
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
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
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
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
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
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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