38,833 research outputs found

    Approaching the ground states of the random maximum two-satisfiability problem by a greedy single-spin flipping process

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    In this brief report we explore the energy landscapes of two spin glass models using a greedy single-spin flipping process, {\tt Gmax}. The ground-state energy density of the random maximum two-satisfiability problem is efficiently approached by {\tt Gmax}. The achieved energy density e(t)e(t) decreases with the evolution time tt as e(t)e()=h(log10t)ze(t)-e(\infty)=h (\log_{10} t)^{-z} with a small prefactor hh and a scaling coefficient z>1z > 1, indicating an energy landscape with deep and rugged funnel-shape regions. For the ±J\pm J Viana-Bray spin glass model, however, the greedy single-spin dynamics quickly gets trapped to a local minimal region of the energy landscape.Comment: 5 pages with 4 figures included. Accepted for publication in Physical Review E as a brief repor

    A Symmetric System of Mixed Painleve III - V Equations and its Integrable Origin

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    A mixed symmetric Painleve III - V model which describes a hybrid of both equations is defined and obtained by successive self-similarity and Dirac Lagrange multiplier reductions from an integrable 4-boson hierarchy.Comment: 22 pages, 1 figure, to appear in J. Phys.

    Complete Fusion Enhancement and Suppression of Weakly Bound Nuclei at Near Barrier Energies

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    We consider the influence of breakup channels on the complete fusion of weakly bound systems in terms of dynamic polarization potentials. It is argued that the enhancement of the cross section at sub-barrier energies may be consistent with recent experimental observations that nucleon transfer, often leading to breakup, is dominant compared to direct breakup. The main trends of the experimental complete fusion cross section for 6,7^{6,7}Li + 209^{209}Bi are analyzed in the framework of the DPP approach.Comment: 12 pages, 2 figure

    Polynomial Realization of sq(2)s\ell_q(2) and Fusion Rules at Exceptional Values of qq

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    Representations of the sq(2)s\ell_q(2) algebra are constructed in the space of polynomials of real (complex) variable for qN=1q^N=1. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general case is formulated

    A simple method for enhanced vibration-based structural health monitoring

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    This study suggests a novel method for structural vibration-based health monitoring for beams which only utilises the first natural frequency of the beam in order to detect and localise a defect. The method is based on the application of a static force in different positions along the beam. It is shown that the application of a static force on a damaged beam induces stresses at the defect which in turn cause changes in the structural natural frequencies. A very simple procedure for damage detection is suggested which uses a static force applied in just one point, in the middle of the beam. Localisation is made using two additional application points of the static force. Damage is modelled as a small notch through the whole width of the beam. The method is demonstrated and validated numerically, using a finite element model of the beam, and experimentally for a simply supported beam. Our results show that the frequency variation with the change of the force application point can be used to detect and in the same time localize very precisely even a very small defect. The method can be extended for health monitoring of other more complicated structures
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