187 research outputs found

    The asymmetry of the dimension 2 gluon condensate: the finite temperature case

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    In this paper, we continue the work begun in a previous article. We compute, in the formalism of local composite operators, the value of the asymmetry in the dimension two condensate for finite temperatures. We find a positive value for the asymmetry, which disappears when the temperature is increased. We also compute the value of the full dimension two condensate for higher temperatures, and we find that it decreases in absolute value, finally disappearing for sufficiently high temperature. We also comment on the temperature dependence of the electric and magnetic components of the condensate separately. We compare our results with the corresponding lattice date found by Chernodub and Ilgenfritz.Comment: 8 pages, 4 figure

    The anomalous dimension of the composite operator A^2 in the Landau gauge

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    The local composite operator A^2 is analysed in pure Yang-Mills theory in the Landau gauge within the algebraic renormalization. It is proven that the anomalous dimension of A^2 is not an independent parameter, being expressed as a linear combination of the gauge beta function and of the anomalous dimension of the gauge fields.Comment: 12 pages, LaTeX2e, final version to appear in Phys. Lett.

    Community Focused Urban Renewal

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    Cities across the nation continue to develop and grow, but in many, rundown industrially zoned lots tend to be left alone and become an eyesore. These sites need to be better utilized by the community living around them. There needs to be a way to develop and design a living community system integrated into the surrounding city and local community with the bonus of being semi-self-sufficient. Combining these new buildings into the existing context of the urban fabric is essential to any growing city. Urban redevelopment of a large site within an already growing city can help to influence further community growth if done with specific methods. This thesis seeks to find an architectural solution to how an urban redevelopment project can renew an area of a downtown district by creating an integrative living system into an existing built community. This urban renewal project consists of utilizing and reusing vacant industrial land. This architectural framework hopes to reconnect new integrative communities into their existing urban fabric while starting and integrating into their own

    The effects of Gribov copies in 2D gauge theories

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    In previous works, we have shown that the Gribov-Zwanziger action, which implements the restriction of the domain of integration in the path integral to the Gribov region, generates extra dynamical effects which influence the infrared behaviour of the gluon and ghost propagator in SU(N) Yang-Mills gauge theories. The latter are in good agreement with the most recent lattice data obtained at large volumes, both in 4D and in 3D. More precisely, the gluon propagator is suppressed and does not vanish at zero momentum, while the ghost propagator keeps a 1/p^2 behaviour for p^2\approx0. Instead, in 2D, the lattice data revealed a vanishing zero momentum gluon propagator and an infrared enhanced ghost, in support of the usual Gribov-Zwanziger scenario. We will now show that the 2D version of the Gribov-Zwanziger action still gives results in qualitative agreement with these lattice data, as the peculiar infrared nature of 2D gauge theories precludes the analogue of the dynamical effect otherwise present in 4D and 3D. Simultaneously, we also observe that the Gribov-Zwanziger restriction serves as an infrared regulating mechanism.Comment: 10 pages, 1 .eps figur

    <i>Psammonema</i> gen. n. and <i>Pseudochromadora</i> Daday, 1889 (Nematoda, Desmodoridae) from sandy sediments of Gazi, Kenya

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    Three new species (Psammonema ovisetosum gen. et sp. n., Pseudochromadora coomansi sp. n.and Pseudochromadora buccobulbosa sp. n.; including all juvenile stages) belonging to a known and to a new genus of the family Desmodoridae (Nematoda, Desmodoroidea) were found in sandy sediments of the intertidal zone in front of the estuarine mangroves of Gazi, Kenya. Psammonema gen. n. differs from Pseudochromadora Daday, 1889 in shape and number of somatic setae in pharyngeal region, in position and shape of lateral alae, and in the anterior position of the amphids on the head capsule. Comments are given on the ecto-symbiotic organisms, feeding habits of the species and on the ontogenetic transformations of some morphological characters

    Dynamical mass generation by source inversion: Calculating the mass gap of the Gross-Neveu model

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    We probe the U(N) Gross-Neveu model with a source-term JΨˉΨJ\bar{\Psi}\Psi. We find an expression for the renormalization scheme and scale invariant source J^\hat{J}, as a function of the generated mass gap. The expansion of this function is organized in such a way that all scheme and scale dependence is reduced to one single parameter d. We get a non-perturbative mass gap as the solution of J^=0\hat{J}=0. In one loop we find that any physical choice for d gives good results for high values of N. In two loops we can determine d self-consistently by the principle of minimal sensitivity and find remarkably accurate results for N>2.Comment: 13 pages, 3 figures, added referenc

    Remarks on the Gribov horizon and dynamical mass generation in Euclidean Yang-Mills theories

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    The effect of the dynamical mass generation on the gluon and ghost propagators in Euclidean Yang-Mills theory in the Landau gauge is analysed within Zwanziger's local formulation of the Gribov horizon.Comment: Work presented at IX Hadron Physics and VII Relativistic Aspects of Nuclear Physics, Angra dos Reis, RJ, Brazil, March 28 to April 03, 200

    Renormalizability of the local composite operator A^2 in linear covariant gauges

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    The local composite operator AÎĽ2A_{\mu}^{2} is analysed within the algebraic renormalization in Yang-Mills theories in linear covariant gauges. We establish that it is multiplicatively renormalizable to all orders of perturbation theory. Its anomalous dimension is computed to two-loops in the MSbar scheme.Comment: 10 pages, LaTeX, final version to appear in Phys. Lett.
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