4,905 research outputs found

    Polynomial and rational solutions of holonomic systems

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    The aim of this paper is to give two new algorithms, which are elimination free, to find polynomial and rational solutions for a given holonomic system associated to a set of linear differential operators in the Weyl algebra D = k where k is a subfield of the complex numbers.Comment: 20 page

    Goldilocks Supersymmetry: Simultaneous Solution to the Dark Matter and Flavor Problems of Supersymmetry

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    Neutralino dark matter is well motivated, but also suffers from two shortcomings: it requires gravity-mediated supersymmetry breaking, which generically violates flavor constraints, and its thermal relic density \Omega is typically too large. We propose a simple solution to both problems: neutralinos freezeout with \Omega ~10-100, but then decay to ~1 GeV gravitinos, which are simultaneously light enough to satisfy flavor constraints and heavy enough to be all of dark matter. This scenario is naturally realized in high-scale gauge-mediation models, ameliorates small scale structure problems, and implies that ``cosmologically excluded'' models may, in fact, be cosmologically preferred.Comment: 4 pages; v2: references added; v3: published versio

    Atomic Bose-Fermi mixed condensates with Boson-Fermion quasi-bound cluster states

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    The boson-fermion atomic bound states (composite fermion) and their roles for the phase structures are studied in a bose-fermi mixed condensate of atomic gas in finite temperature and density. The two-body scattering equation is formulated for a boson-fermion pair in the mixed condensate with the Yamaguchi-type potential. By solving the equation, we evaluate the binding energy of a composite fermion, and show that it has small T-dependence in the physical region, because of the cancellation of the boson- and fermion- statistical factors in the equation. We also calculate the phase structure of the BF mixed condensate under the equilibrium B+F -> BF, and discuss the role of the composite fermions: the competitions between the degenerate state of the composite fermions and the Bose-Einstein condensate (BEC) of isolated bosons. The criterion for the BEC realization is obtained from the algebraically-derived phase diagrams at T=0.Comment: 5 pages, 3 figure

    Numerical Simulation of Permanent Magnet Method for Measuring Critical Current Density in Superconducting Film: Dominant Experimental Conditions for Crack Detection

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    AbstractThe scanning permanent magnet method for measuring the critical current density in a high-temperature superconduct- ing (HTS) film has been reproduced numerically. For this purpose, a numerical code has been developed for analyzing the time evolution of a shielding current density in an HTS film with a crack. The results of computations show that the attractive force Fr and repulsive one Fa are observed near the endpoints of the crack when the symmetry axis of the magnet approaches the crack. In addition, the both forces, Fr and Fa, have the maximum value only when the magnet is located above the crack. This means that the crack size and position can be estimated by using the scanning method
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