1,296 research outputs found

    Dirac Variables and Zero Modes of Gauss Constraint in Finite-Volume Two-Dimensional QED

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    The finite-volume QED1+1_{1+1} is formulated in terms of Dirac variables by an explicit solution of the Gauss constraint with possible nontrivial boundary conditions taken into account. The intrinsic nontrivial topology of the gauge group is thus revealed together with its zero-mode residual dynamics. Topologically nontrivial gauge transformations generate collective excitations of the gauge field above Coleman's ground state, that are completely decoupled from local dynamics, the latter being equivalent to a free massive scalar field theory.Comment: 13 pages, LaTe

    Thermal correlators of anyons in two dimensions

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    The anyon fields have trivial α\alpha-commutator for α\alpha not integer. For integer α\alpha the commutators become temperature-dependent operator valued distributions. The nn-point functions do not factorize as for quasifree states.Comment: 14 pages, LaTeX (misprints corrected, a reference added

    Anyons and the Bose-Fermi duality in the finite-temperature Thirring model

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    Solutions to the Thirring model are constructed in the framework of algebraic QFT. It is shown that for all positive temperatures there are fermionic solutions only if the coupling constant is λ=2(2n+1)π,nN\lambda=\sqrt{2(2n+1)\pi}, n\in {\bf N}. These fermions are inequivalent and only for n=1n=1 they are canonical fields. In the general case solutions are anyons. Different anyons (which are uncountably many) live in orthogonal spaces and obey dynamical equations (of the type of Heisenberg's "Urgleichung") characterized by the corresponding values of the statistic parameter. Thus statistic parameter turns out to be related to the coupling constant λ\lambda and the whole Hilbert space becomes non-separable with a different "Urgleichung" satisfied in each of its sectors. This feature certainly cannot be seen by any power expansion in λ\lambda. Moreover, since the latter is tied to the statistic parameter, it is clear that such an expansion is doomed to failure and will never reveal the true structure of the theory. The correlation functions in the temperature state for the canonical dressed fermions are shown by us to coincide with the ones for bare fields, that is in agreement with the uniqueness of the τ\tau-KMS state over the CAR algebra (τ\tau being the shift automorphism). Also the α\alpha-anyon two-point function is evaluated and for scalar field it reproduces the result that is known from the literature.Comment: 25 pages, LaTe

    An Analysis and Forecast of Software and Services Research in Bulgaria

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    In the last 40 years much has been achieved in Software Engineering research and still more is to be done. Although significant progress is being made on several fronts in Service-Oriented Architecture (SOA), there is still no set of clear, central themes to focus research activity on. A task within the EU FP7 Sister project aimed at defining research priorities for the Faculty of Mathematics and Informatics (Sofia University) in the area of Software and Services. A dedicated methodology was proposed and developed, based on various sources of information. The information accumulated was systematised and processed according to this methodology. The final results obtained are described and discussed here.* The work reported in this paper is partly supported by the SISTER project, funded by the European Commission in FP7-SP4 Capacities via agreement no. 205030

    Tannins as Antiviral Agents

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    Tannins possess a variety of biological effects, not a small part of which is of medical significance. Tannins, isolated from plants as well as synthetically obtained, manifest activity against a large spectrum of viruses: enteroviruses (polio- and coxsackie-), caliciviruses (feline calicivirus, mouse norovirus), rotavirus, influenza virus A, rhabdo- (vesicular stomatitis virus), paramyxoviruses (Sendai and Newcastle disease viruses), human immunodeficiency virus, herpes simplex virus, and adenoviruses. A special importance merits several ellagitannins manifesting pronounced effects against herpes simplex virus type 1 and 2 and on some herpes viruses affecting domestic animals, causing diseases of economic importance. An advantage of ellagitannins as anti-herpesvirus agents is that they have a non-nucleoside structure. Their targets are virus-specific proteins, so they retain activity against acyclovir-resistant strains of HSV types 1 and 2. Besides, these tannins manifest a synergistic effect with acyclovir when combined. Some initial results on their mechanism of action were carried out. In addition, it was found that most of the tannins have antioxidant properties in experimental models in vitro as well as in experimental influenza viral infection in mice

    Characteristics of Petit verdot grape variety (Vitis vinifera L.) grown in Tikveš vineyards

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    Research is being performed to the variety of Petit verdot. The vineyards are sited on the Lepovo-Tikveš vineyards, in the property of Bovin winery. Plantation is started in 2008 with certified plantation material, 2.4 m planting distance between rows, and 1.0 m distance between vines in a row. The training system is Guyot two arms, with 20 eyelets leaving the vine. Some optimal agro-technical and ampelo-technical measures are applied. The plantation is under drip irrigation system. During the research period (2011– 2012) the following items were included: yield (kg/vine), chemical composition of grape must (sugar, total acid, pH), and chemical analysis of wine. The results show considerable variation in yield interest (14.48), which is due to the age of the crop, whether it is in the second (2011) or in the third (2012) year of birth. The must contains 230 g/L sugar and 5.5 g/L total acids, average for the test period. The wine has a high content of extract (40 g/L) and 13.11% vol alcohol, which is due to selective grape harvesting and the way of vinification (winemaking)

    Suppression of serine protease secretion and sporulation in Bacillus subtilis by detergents

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    In Bacillus subtilis grown under aeration at 37° for 24 h in liquid nutrient medium containing the nonionic detergents octylphenol-polyethylene glycol ether or polyoxyethylene monocetyl ether, increasing the concentrations of the detergents led to a decrease in the amount of protease secreted from the cells and abolished sporulation. Possible mechanisms by which these detergents caused these actions are discussed

    On Supergroups with Odd Clifford Parameters and Supersymmetry with Modified Leibniz Rule

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    We investigate supergroups with Grassmann parameters replaced by odd Clifford parameters. The connection with non-anticommutative supersymmetry is discussed. A Berezin-like calculus for odd Clifford variables is introduced. Fermionic covariant derivatives for supergroups with odd Clifford variables are derived. Applications to supersymmetric quantum mechanics are made. Deformations of the original supersymmetric theories are encountered when the fermionic covariant derivatives do not obey the graded Leibniz property. The simplest non-trivial example is given by the N=2 SQM with a real (1,2,1)(1,2,1) multiplet and a cubic potential. The action is real. Depending on the overall sign ("Euclidean" or "Lorentzian") of the deformation, a Bender-Boettcher pseudo-hermitian hamiltonian is encountered when solving the equation of motion of the auxiliary field. A possible connection of our framework with the Drinfeld twist deformation of supersymmetry is pointed out.Comment: Final version to be published in Int. J. Mod. Phys. A; 20 page

    Relationship Between Atomic Polar Tensors and Bond Polar Parameters Formulations of Infrared Intensities

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    The mathematical and physical aspects of the relationship between the atomic polar tensors and bond polar parameters formulations of vibrational intensities in infrared spectra are discussed. The theoretical considerations are illustrated with parallel applications of the two approaches in analysing experimental intensity data for ethane, methyl chloride and H2O
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