2,132 research outputs found

    On The Entanglement Entropy For Gauge Theories

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    We propose a definition for the entanglement entropy of a gauge theory on a spatial lattice. Our definition applies to any subset of links in the lattice, and is valid for both Abelian and Non-Abelian gauge theories. For ZN\mathbb{Z}_N and U(1)U(1) theories, without matter, our definition agrees with a particular case of the definition given by Casini, Huerta and Rosabal. We also argue that in general, both for Abelian and Non-Abelian theories, our definition agrees with the entanglement entropy calculated using a definition of the replica trick. Our definition, however, does not agree with some standard ways to measure entanglement, like the number of Bell pairs which can be produced by entanglement distillation.Comment: 29 pages, 4 figures; section on Extended Lattice Construction revised and some changes in referencing; some of the discussion of the replica trick changed; section on SU(2) revised for clarit

    Coherence resonance in an unijunction transistor relaxation oscillator

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    The phenomenon of coherence resonance (CR) is investigated in an unijunction transistor relaxation oscillator (UJT-RO) and quantified by estimating the normal variance (NV). Depending upon the measuring points two types of NV curves have been obtained. We have observed that the degradations in coherency at higher noise amplitudes in our system is probably the result of direct interference of coherent oscillations and the stochastic perturbation. Degradation of coherency may be minimal if this direct interference of noise and coherent oscillations is eliminated.Comment: 4 pages, Coherence resonace, Uni junction relaxation oscillato

    Electrophoresis of a polyelectrolyte through a nanopore

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    A hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through a nanopore is presented. It is assumed that the speed is determined by a balance of electrical and viscous forces arising from within the pore and that classical continuum electrostatics and hydrodynamics may be considered applicable. An explicit formula for the translocation speed as a function of the pore geometry and other physical parameters is obtained and is shown to be consistent with experimental measurements on DNA translocation through nanopores in silicon membranes. Experiments also show a weak dependence of the translocation speed on polymer length that is not accounted for by the present model. It is hypothesized that this is due to secondary effects that are neglected here.Comment: 5 pages, 2 column, 2 figure

    Taxonomic studies of Eulophid parasitoids (Hymenoptera: Chalcidoidea) collected from Uttarakhand, India

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    A sound taxonomic knowledge base is a prerequisite for effective conservation, environment assessment, ecological research, management and sustainable use of biological resources. Parasitoids are the major component of the biocontrol, so the correct identification of the parasitoid is very important task. Eulophidae is a large family of the superfamily Chalcidoidea and comprises promising biocontrol agents for the control of insect pests causing harm to agricultural ecosystem. The present study has been done to provide the account and occurrence of 4 genera belonging to subfamily Entedoninae, Eulophinae and Tetrastichinae. Entedon costalis Dalman, Diglyphus horticola Khan, Hemiptarsenus varicornis (Girault), and Neotrichoporoides viridimaculatus (Fullaway) was collected from Uttarakhand (India) and described in detail with additional morphological characters that aids in clear identification of the parasitoids. Entedon costalis is recorded from this region with additional characters for identification

    Semi-analytical Solution of Dirac equation in Schwarzschild Geometry

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    Separation of the Dirac equation in the spacetime around a Kerr black hole into radial and angular coordinates was done by Chandrasekhar in 1976. In the present paper, we solve the radial equations in a Schwarzschild geometry semi-analytically using Wentzel-Kramers-Brillouin approximation (in short WKB) method. Among other things, we present analytical expression of the instantaneous reflection and transmission coefficients and the radial wave functions of the Dirac particles. Complete physical parameter space was divided into two parts depending on the height of the potential well and energy of the incoming waves. We show the general solution for these two regions. We also solve the equations by a Quantum Mechanical approach, in which the potential is approximated by a series of steps and found that these two solutions agree. We compare solutions of different initial parameters and show how the properties of the scattered wave depend on these parameters.Comment: RevTex, 11 Latex pages and 12 Figures ; Classical and Quantum Gravity (in Press) (1999

    Addressing \mu-b_\mu and proton lifetime problems and active neutrino masses in a U(1)^\prime-extended supergravity model

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    We present a locally supersymmetric extension of the minimal supersymmetric Standard Model (MSSM) based on the gauge group SU(3)C×SU(2)L×U(1)Y×U(1)SU(3)_C\times SU(2)_L\times U(1)_Y\times U(1)^\prime where, except for the supersymmetry breaking scale which is fixed to be 1011\sim 10^{11} GeV, we require that all non-Standard-Model parameters allowed by the {\it local} spacetime and gauge symmetries assume their natural values. The U(1)U(1)^\prime symmetry, which is spontaneously broken at the intermediate scale, serves to ({\it i}) explain the weak scale magnitudes of μ\mu and bμb_\mu terms, ({\it ii}) ensure that dimension-3 and dimension-4 baryon-number-violating superpotential operators are forbidden, solving the proton-lifetime problem, ({\it iii}) predict {\it bilinear lepton number violation} in the superpotential at just the right level to accommodate the observed mass and mixing pattern of active neutrinos (leading to a novel connection between the SUSY breaking scale and neutrino masses), while corresponding trilinear operators are strongly supppressed. The phenomenology is like that of the MSSM with bilinear R-parity violation, were the would-be lightest supersymmetric particle decays leptonically with a lifetime of 1012108\sim 10^{-12}-10^{-8} s. Theoretical consistency of our model requires the existence of multi-TeV, stable, colour-triplet, weak-isosinglet scalars or fermions, with either conventional or exotic electric charge which should be readily detectable if they are within the kinematic reach of a hadron collider. Null results of searches for heavy exotic isotopes implies that the re-heating temperature of our Universe must have been below their mass scale which, in turn, suggests that sphalerons play a key role for baryogensis. Finally, the dark matter cannot be the weakly interacting neutralino.Comment: 33 pages, 2 figures, Discussion on proton decay and radiative neutrino masses augmented, and references adde

    The dissolution and solid-state behaviours of coground ibuprofen–glucosamine HCl

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    The cogrinding technique is one of most effective methods for improving the dissolution of poorly water-soluble drugs and it is superior to other approaches from an economical as well as an environmental standpoint, as the technique does not require any toxic organic solvents. Present work explores the role of d-glucosamine HCl (GL) as a potential excipient to improve dissolution of a low melting point drug, ibuprofen (Ibu), using physical mixtures and coground formulations. The dissolution of the poorly soluble drug has been improved by changing the ratio of Ibu:GL and also grinding time. The results also showed that although GL can enhance the solubility of Ibu, it also reduces pH around the Ibu particles which led to poor dissolution performance when the concentration of GL is high. The effect of GL on the solubility of Ibu could be misleading if the pH of the final solution was not measured. Grinding reduced the particle size of GL significantly but in case of Ibu it was less effective. Solid state analysis (XRPD, DSC, and FT-IR) showed that ibuprofen is stable under grinding conditions, but the presence of high concentration of GL in samples subjected to high grinding times caused changes in FT-IR spectrum of Ibu which could be due to intermolecular hydrogen bond or esterification between the carboxylic acid group in the ibuprofen and hydroxyl group in the GL
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