30,260 research outputs found

    Interest Arbitration, Outcomes, and the Incentive to Bargain

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    This study develops a model of bargaining that demonstrates that an interest arbitration procedure will encourage negotiated settlements to the extent that risk aversion dominates the preferences of the parties and there is uncertainty regarding the arbitrator\u27s behavior. The authors conclude that it is likely that risk aversion does dominate preferences, but the evidence is not conclusive. They also argue that uncertainty may be reduced over time for various reasons, leading to increased use of arbitration and a convergence between the terms of negotiated and arbitrated agreements

    The Density of States Method at Finite Chemical Potential

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    We study the density of states method to explore the phase diagram of the chiral transition on the temperature and quark chemical potential plane. Four quark flavors are used in the analysis. Though the method is quite expensive small lattices show an indication for a triple-point connecting three different phases on the phase diagram.Comment: 5 pages, 6 figures, talk given at 'Extreme QCD', August 2-5 2005, Swansea, Wales, U

    Complex Langevin dynamics for dynamical QCD at nonzero chemical potential: a comparison with multi-parameter reweighting

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    We study lattice QCD at non-vanishing chemical potential using the complex Langevin equation. We compare the results with multi-parameter reweighting both from μ=0\mu=0 and phase quenched ensembles. We find a good agreement for lattice spacings below \approx0.15 fm. On coarser lattices the complex Langevin approach breaks down. Four flavors of staggered fermions are used on Nt=4,6N_t=4, 6 and 8 lattices. For one ensemble we also use two flavors to investigate the effects of rooting.Comment: 10 pages, 11 figures, PRD version, minor change

    Unequal Intra-layer Coupling in a Bilayer Driven Lattice Gas

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    The system under study is a twin-layered square lattice gas at half-filling, being driven to non-equilibrium steady states by a large, finite `electric' field. By making intra-layer couplings unequal we were able to extend the phase diagram obtained by Hill, Zia and Schmittmann (1996) and found that the tri-critical point, which separates the phase regions of the stripped (S) phase (stable at positive interlayer interactions J_3), the filled-empty (FE) phase (stable at negative J_3) and disorder (D), is shifted even further into the negative J_3 region as the coupling traverse to the driving field increases. Many transient phases to the S phase at the S-FE boundary were found to be long-lived. We also attempted to test whether the universality class of D-FE transitions under a drive is still Ising. Simulation results suggest a value of 1.75 for the exponent gamma but a value close to 2.0 for the ratio gamma/nu. We speculate that the D-FE second order transition is different from Ising near criticality, where observed first-order-like transitions between FE and its "local minimum" cousin occur during each simulation run.Comment: 29 pages, 19 figure

    The intrinsic electrical equivalent circuit of a laser diode

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    The basic electrical equivalent circuit of a laser diode is derived. The effects of spontaneous emission and self-pulsations are included. It is found that self-pulsations are represented by a negative resistance in the model. Application of this model suggests purely electronic methods of suppressing relaxation oscillations in laser diodes

    Integral Constraints On cosmological Perturbations and their Energy

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    We show the relation between Traschen's integral equations and the energy, and ``position of the centre of mass'', of the matter perturbations in a Robertson-Walker spacetime. When the perturbations are ``localised'' we get a set of integral constraints that includes hers. We illustrate them on a simple example.Comment: 19 pages, Tex file, submitted to Classical and Quantum Gravit

    Coupling mechanism of gain-guided integrated semiconductor laser arrays

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    It is shown that a gain-guided laser array couples via propagating fields rather than the evanescent mode coupling typically responsible for directional coupling in passive (directional couplers) and active (laser array) devices. We show that these phase-locked modes exhibit an interference pattern, in the junction plane, which arises from the curvature of the phase fronts of optical fields of the interacting lasers. The experimental results are interpreted with the aid of a simple theoretical model, and the effect of the observed mode pattern on the coupling of gain-guided lasers is discussed

    Chirped arrays of diode lasers for supermode control

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    We propose nonuniform structures of phase-locked diode lasers, which make it possible to discriminate efficiently against all the higher order array supermodes (lateral modes). In these nonuniform arrays, the effective mode index in each channel varies across the array. Consequently, the envelopes of the various supermodes, including the highest order one, differ significantly from each other. Thus, by proper tailoring of the gain distribution across the array, one can conveniently select the fundamental supermode. Such fundamental supermode oscillation is essential in order to obtain single lobe, diffraction limited beams and minimal spectral spread from phase-locked laser arrays
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