4,327 research outputs found

    Generating Erler-Schnabl-type Solution for Tachyon Vacuum in Cubic Superstring Field Theory

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    We study a new set of identity-based solutions to analyze the problem of tachyon condensation in open bosonic string field theory and cubic superstring field theory. Even though these identity-based solutions seem to be trivial, it turns out that after performing a suitable gauge transformation, we are left with the known Erler-Schnabl-type solutions which correctly reproduce the value of the D-brane tension. This result shows explicitly that how a seemingly trivial solution can generate a non-trivial configuration which precisely represents to the tachyon vacuum.Comment: 22 pages, references added, appendix added, 2 subsections adde

    Large NN reduction with the Twisted Eguchi-Kawai model

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    We examine the breaking of ZNZ_N symmetry recently reported for the Twisted Eguchi-Kawai model (TEK). We analyse the origin of this behaviour and propose simple modifications of twist and lattice action that could avoid the problem. Our results show no sign of symmetry breaking and allow us to obtain values of the large NN infinite volume string tension in agreement with extrapolations from results based upon straightforward methods.Comment: latex file 14 pages, 4 figure

    Comments on regularization of identity based solutions in string field theory

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    We analyze the consistency of the recently proposed regularization of an identity based solution in open bosonic string field theory. We show that the equation of motion is satisfied when it is contracted with the regularized solution itself. Additionally, we propose a similar regularization of an identity based solution in the modified cubic superstring field theory.Comment: 24 pages, two subsections added, two references adde

    Gluino zero-modes for non-trivial holonomy calorons

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    We couple fermion fields in the adjoint representation (gluinos) to the SU(2) gauge field of unit charge calorons defined on R^3 x S_1. We compute corresponding zero-modes of the Dirac equation. These are relevant in semiclassical studies of N=1 Super-symmetric Yang-Mills theory. Our formulas, show that, up to a term proportional to the vector potential, the modes can be constructed by different linear combinations of two contributions adding up to the total caloron field strength.Comment: 17 pages, 3 Postscript figures, late

    Scaling Analysis of Improved Actions for Pure SU(3) Gauge Theory

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    We have explored the behaviour of some improved actions based on a nonperturbative renormalization group (RG) analysis in coupling space. We calculate the RG flow in two-coupling space (\boneone,\bonetwo) and examine the restoration of rotational invariance and the scaling of physical quantities (Tc/σ)(T_c/\sqrt{\sigma}).Comment: LATTICE98(improvement

    Non-Abelian Vortices on the Torus

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    We study periodic arrays of non-Abelian vortices in an SU(N)×U(1)SU(N) \times U(1) gauge theory with NfN_f flavors of fundamental matter multiplets. We carefully discuss the corresponding twisted boundary conditions on the torus and propose an ansatz to solve the first order Bogomolnyi equations which we find by looking to a bound of the energy. We solve the equations numerically and construct explicit vortex solutions

    Non-affine mechanics of entangled networks inspired by intermediate filaments

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    Inspired by massive intermediate filament (IF) reorganization in superstretched epithelia, we examine computationally the principles controlling the mechanics of a set of entangled filaments whose ends slide on the cell boundary. We identify an entanglement metric and threshold beyond which random loose networks respond non-affinely and nonlinearly to stretch by self-organizing into structurally optimal star-shaped configurations. A simple model connecting cellular and filament strains links emergent mechanics to cell geometry, network topology, and filament mechanics. We identify a safety net mechanism in IF networks and provide a framework to harness entanglement in soft fibrous materials.Comment: 23 pages, 16 figures; expanded discussion of non-affinity, added supplementary data on interaction with frictional background at fast loading rates, modified title, results unchange

    Numerical study of Yang-Mills classical solutions on the twisted torus

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    We use the lattice cooling method to investigate the structure of some gauge fixed SU(2) Yang-Mills classical solutions of the euclidean equations of motion which are defined in the 3-torus with symmetric twisted boundary conditions.Comment: 20pp (fig.included

    Conservation laws and tachyon potentials in the sliver frame

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    Conservation laws have provided an elegant and efficient tool to evaluate the open string field theory interaction vertex, they have been originally implemented in the case where the string field is expanded in the Virasoro basis. In this work we derive conservation laws in the case where the string field is expanded in the so-called sliver L0\mathcal{L}_0-basis. As an application of these conservation laws derived in the sliver frame, we compute the open string field action relevant to the tachyon condensation and in order to present not only an illustration but also an additional information, we evaluate the action without imposing a gauge choice.Comment: 26 pages, some typos fixed, comments added, references adde

    La comunidad de ácaros Mesostigmata (Acari, Mesostigmata) en el dosel arbóreo de bosques de pícea en Irlanda en comparación con la presente en hábitats muscícolas edáficos

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    The main aim of this study was to examine the communities of mesostigmatid mites occurring in Irish Sitka spruce (Picea sitchensis) canopies or inhabiting moss, either in the canopy or on the soil surface, and to discover whether a characteristic assemblage of species occurs in particular habitat patches (ground vs. aerial). Twenty two species of Mesostigmata were recorded, of which five occurred exclusively in arboreal microhabitats. All three species of Zerconidae collected were unique to the canopy and moss mats on the tree branches. Trachytes aegrota (C.L. Koch, 1841) was recorded for the first time in Ireland and some comments about its distribution are made. Multivariate analysis indicated that the arboreal mesostigmatid community is not just a subset of the assemblage occurring in moss on soil or trunks and that it appears to be more homogeneous than those occurring on the soil surface.El objetivo principal de este trabajo fue estudiar en Irlanda las comunidades de ácaros Mesostigmata del dosel arbóreo de bosques de Picea sitchensis y en el musgo desarrollado tanto en zonas aéreas como en la superficie edáfica, con el fin de determinar si la estructura y composición de éstas comunidades variaba entre los hábitats diferenciales (edáficos vs. aéreos). Se obtuvieron 22 especies de ácaros Mesostigmata, de las cuales 5 aparecieron solamente en micro-hábitats arbóreos. Las especies de la familia Zerconidae recogidas en este estudio se encontraron exclusivamente en ramas y musgos desarrollados en el dosel. Trachytes aegrota (C.L. Koch, 1841), es citado por primera vez para Irlanda. Se ofrecen asimismo comentarios sobre la distribución de esta especie. El análisis multivariante de los resultados indicó que las poblaciones arbóreas de ácaros Mesostigmata no son un mero subconjunto estructural sino que forman una comunidad diferencial respecto a las presentes en hábitats muscícolas del tronco o del medio edáfico, y son más homogéneas que las existentes en la superficie del suelo
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