4,118 research outputs found

    Microscopic Entropy of Non-dilatonic Branes: a 2D approach

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    We investigate non-dilatonic p-branes in the near-extremal, near-horizon regime. A two-dimensional gravity model, obtained from dimensional reduction, gives an effective description of the brane. We show that the AdS_p+2/CFT_p+1 correspondence at finite temperature admits an effective description in terms of a AdS_2/CFT_1 duality endowed with a scalar field, which breaks the conformal symmetry and generates a non-vanishing central charge. The entropy of the CFT_1 is computed using Cardy formula. Fixing in a natural way a free, dimensionless, parameter introduced in the model by a renormalization procedure, we find exact agreement between the CFT_1 entropy and the Bekenstein-Hawking entropy of the brane.Comment: 10 pages, no figure

    The Moduli Space and Monodromies of the N=2N=2 Supersymmetric Yang-Mills Theory with any Lie Gauge Groups

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    We propose a unified scheme for finding the hyperelliptic curve of N=2N=2 SUSY YM theory with any Lie gauge groups. Our general scheme gives the well known results for classical gauge groups and exceptional G2G_2 group. In particular, we present the curve for the exceptional gauge groups F4,E6,7,8F_4, E_{6,7,8} and check consistency condition for them. The exact monodromies and the dyon spectrum of these theories are determined. We note that for any Lie gauge groups, the exact monodromies could be obtained only from the Cartan matrix.Comment: 17 pages, LaTeX fil

    UTILIZATION OF THE ICELANDIC COD STOCK IN A MULTISPECIES CONTEXT

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    The purpose of this paper is to discuss rules for deciding Total Allowable Catch (TAC) for Icelandic cod. For this purpose, a bioeconomic model describing harvesting and processing of cod, capelin, and shrimp in the Icelandic marine ecosystem is constructed and estimated. The model is used to analyze the probable effects of harvesting strategies on biomass, catch, and economic benefits from the exploitation of these species. Simulations are used to investigate probability profiles of biological and economic variables, taking into account inaccuracies in assessments and uncertainties in predictions. Optimal harvesting strategies are also investigated using a deterministic version of the model and taking into account problems of unemployment, overcapacity, and aversion to fluctuations in consumption. The analysis shows that it is beneficial to reduce fishing from the cod stock in order to allow the stock to recover to its optimum size. This increase in the cod stock will result in big decreases in the catch of capelin and shrimp.Resource /Energy Economics and Policy,

    Electromagnetic Corrections in Partially Quenched Chiral Perturbation Theory

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    We introduce photons in Partially Quenched Chiral Perturbation Theory and calculate the resulting electromagnetic loop-corrections at NLO for the charged meson masses and decay constants. We also present a numerical analysis to indicate the size of the different corrections. We show that several phenomenologically relevant quantities can be calculated consistently with photons which couple only to the valence quarks, allowing the use of gluon configurations produced without dynamical photons.Comment: 11 page

    The Moduli Space of the N=2N=2 Supersymmetric G2G_{2} Yang-Mills Theory

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    We present the hyper-elliptic curve describing the moduli space of the N=2 supersymmetric Yang-Mills theory with the G2G_2 gauge group. The exact monodromies and the dyon spectrum of the theory are determined. It is verified that the recently proposed solitonic equation is also satisfied by our solution.Comment: Complete set of monodromies are included. To be published in Phys.lett.

    Holographic Superconductors with Lifshitz Scaling

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    Black holes in asymptotically Lifshitz spacetime provide a window onto finite temperature effects in strongly coupled Lifshitz models. We add a Maxwell gauge field and charged matter to a recently proposed gravity dual of 2+1 dimensional Lifshitz theory. This gives rise to charged black holes with scalar hair, which correspond to the superconducting phase of holographic superconductors with z > 1 Lifshitz scaling. Along the way we analyze the global geometry of static, asymptotically Lifshitz black holes at arbitrary critical exponent z > 1. In all known exact solutions there is a null curvature singularity in the black hole region, and, by a general argument, the same applies to generic Lifshitz black holes.Comment: 23 pages, 4 figures; v2: added references; v3: matches published versio

    Three-Flavor Partially Quenched Chiral Perturbation Theory at NNLO for Meson Masses and Decay Constants

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    We discuss Partially Quenched Chiral Perturbation Theory (PQχ\chiPT) and possible fitting strategies to Lattice QCD data at next-to-next-to-leading order (NNLO) in the mesonic sector. We also present a complete calculation of the masses of the charged pseudoscalar mesons, in the supersymmetric formulation of PQχ\chiPT. Explicit analytical results are given for up to three nondegenerate sea quark flavors, along with the previously unpublished expression for the pseudoscalar meson decay constant for three nondegenerate sea quark flavors. The numerical analysis in this paper demonstrates that the corrections at NNLO are sizable, as expected from earlier work.Comment: 31 pages, numerical discussion extended including convergence NLO to NNL

    A not so brief commentary on cosmological entropy bounds

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    There has been, quite recently, a discussion on how holographic-inspired bounds might be used to encompass the present-day dark energy and early-universe inflation into a single paradigm. In the current treatment, we point out an inconsistency in the proposed framework and then provide a viable resolution. We also elaborate on some of the implications of this framework and further motivate the proposed holographic connection. The manuscript ends with a more speculative note on cosmic time as an emergent (holographically induced) construct.Comment: 12 pages and Revtex; (v2) reference added and a few cosmetic change
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