58,887 research outputs found

    Non-local 2D Generalized Yang-Mills theories on arbitrary surfaces with boundary

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    The non-local generalized two dimensional Yang Mills theories on an arbitrary orientable and non-orientable surfaces with boundaries is studied. We obtain the effective action of these theories for the case which the gauge group is near the identity, UIU\simeq I. Furthermore, by obtaining the effective action at the large-N limit, it is shown that the phase structure of these theories is the same as that obtain for these theories on orientable and non-orientable surface without boundaries. It is seen that the ϕ2\phi^2 model of these theories on an arbitrary orientable and non-orientable surfaces with boundaries have third order phase transition only on g=0g=0 and r=1r=1 surfaces, with modified area A~+A/2\tilde{A}+{\cal A}/2 for orientable and Aˉ+A\bar{A}+\mathcal{A} for non-orientable surfaces respectivly.Comment: 10 pages, no figures, late

    A perturbative analysis of tachyon condensation

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    Tachyon condensation in the open bosonic string is analyzed using a perturbative expansion of the tachyon potential around the unstable D25-brane vacuum. Using the leading terms in the tachyon potential, Pad\'e approximants can apparently give the energy of the stable vacuum to arbitrarily good accuracy. Level-truncation approximations up to level 10 for the coefficients in the tachyon potential are extrapolated to higher levels and used to find approximants for the full potential. At level 14 and above, the resulting approximants give an energy less than -1 in units of the D25-brane tension, in agreement with recent level-truncation results by Gaiotto and Rastelli. The extrapolated energy continues to decrease below -1 until reaching a minimum near level 26, after which the energy turns around and begins to approach -1 from below. Within the accuracy of this method, these results are completely consistent with an energy which approaches -1 as the level of truncation is taken to be arbitrarily large.Comment: 8 pages, 3 eps figures, Latex; v2: typo correcte

    The use of linear programming in least-cost feed compounding

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    Intensive types of livestock production such as poultry and pigs promise to become of increasing importance in New Zealand agriculture. In such enterprises, feed costs constitute a very high proportion of total variable costs. Any method of computing low cost feeds is obviously of great importance. Linear programming is one such method which has been widely used overseas. In this bulletin Mr Taylor applies this method to the problem of formulating least-cost commercial feed compounds for broiler chickens

    Some comments about Schwarzschield black holes in Matrix theory

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    In the present paper we calculate the statistical partition function for any number of extended objects in Matrix theory in the one loop approximation. As an application, we calculate the statistical properties of K clusters of D0 branes and then the statistical properties of K membranes which are wound on a torus.Comment: 15 page

    A method for the reduction of aerodynamic drag of road vehicles

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    A method is proposed for the reduction of the aerodynamic drag of bluff bodies, particularly for application to road transport vehicles. This technique consists of installation of panels on the forward surface of the vehicle facing the airstream. With the help of road tests, it was demonstrated that the attachment of proposed panels can reduce aerodynamic drag of road vehicles and result in significant fuel cost savings and conservation of energy resources

    Matrix embeddings on flat R3R^3 and the geometry of membranes

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    We show that given three hermitian matrices, what one could call a fuzzy representation of a membrane, there is a well defined procedure to define a set of oriented Riemann surfaces embedded in R3R^3 using an index function defined for points in R3R^3 that is constructed from the three matrices and the point. The set of surfaces is covariant under rotations, dilatations and translation operations on R3R^3, it is additive on direct sums and the orientation of the surfaces is reversed by complex conjugation of the matrices. The index we build is closely related to the Hanany-Witten effect. We also show that the surfaces carry information of a line bundle with connection on them. We discuss applications of these ideas to the study of holographic matrix models and black hole dynamics.Comment: 41 pages, 3 figures, uses revtex4-1. v2: references added, corrected an error in attribution of idea

    Working Group 5: Measurements technology and active experiments

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    Technology issues identified by working groups 5 are listed. (1) New instruments are needed to upgrade the ability to measure plasma properties in space. (2) Facilities should be developed for conducting a broad range of plasma experiments in space. (3) The ability to predict plasma weather within magnetospheres should be improved and a capability to modify plasma weather developed. (4) Methods of control of plasma spacecraft and spacecraft plasma interference should be upgraded. (5) The space station laboratory facilities should be designed with attention to problems of flexibility to allow for future growth. These issues are discussed

    Homotopy Lie Superalgebra in Yang-Mills Theory

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    The Yang-Mills equations are formulated in the form of generalized Maurer-Cartan equations, such that the corresponding algebraic operations are shown to satisfy the defining relations of homotopy Lie superalgebra.Comment: LaTeX2e, 10 page
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