4,268 research outputs found

    Loss-Avoidance and Forward Induction in Experimental Coordination Games

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    We report experiments on how players select among multiple Pareto-ranked equilibria in a coordination game. Subjects initially choose inefficient equilibria. Charging a fee to play (which makes initial equilibria money-losing) creates coordination on better equilibria. When fees are optional, improved coordination is consistent with forward induction. But coordination improves even when subjects must pay the fee (forward induction does not apply). Subjects appear to use a "loss-avoidance" selection principle: they expect others to avoid strategies that always result in losses. Loss-avoidance implies that "mental accounting" of outcomes can affect choices in games

    Survival before annihilation in Psi-prime decays

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    We extend the simple scenario for Ψ\Psi' decays suggested a few years ago. The ccˉc\bar c pair in the Ψ\Psi' does not annihilate directly into three gluons but rather survives before annihilating. An interesting prediction is that a large fraction of all Ψ\Psi' decays could originate from the Ψηc(3π)\Psi' \to \eta_{c} (3\pi) channel which we urge experimentalists to identify. Our model solves the problem of the apparent hadronic excess in Ψ\Psi' decays as well as the ρπ\rho\pi puzzle since, in our view, the two-body decays of the Ψ\Psi' are naturally of electromagnetic origin. Further tests of this picture are proposed, e.g. J/Ψb1ηJ/\Psi \to b_{1}\eta.Comment: 6 pages, no figur

    Phase Space Models for Stochastic Nonlinear Parabolic Waves: Wave Spread and Singularity

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    We derive several kinetic equations to model the large scale, low Fresnel number behavior of the nonlinear Schrodinger (NLS) equation with a rapidly fluctuating random potential. There are three types of kinetic equations the longitudinal, the transverse and the longitudinal with friction. For these nonlinear kinetic equations we address two problems: the rate of dispersion and the singularity formation. For the problem of dispersion, we show that the kinetic equations of the longitudinal type produce the cubic-in-time law, that the transverse type produce the quadratic-in-time law and that the one with friction produces the linear-in-time law for the variance prior to any singularity. For the problem of singularity, we show that the singularity and blow-up conditions in the transverse case remain the same as those for the homogeneous NLS equation with critical or supercritical self-focusing nonlinearity, but they have changed in the longitudinal case and in the frictional case due to the evolution of the Hamiltonian

    Controlling the dynamics of a coupled atom-cavity system by pure dephasing : basics and potential applications in nanophotonics

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    The influence of pure dephasing on the dynamics of the coupling between a two-level atom and a cavity mode is systematically addressed. We have derived an effective atom-cavity coupling rate that is shown to be a key parameter in the physics of the problem, allowing to generalize the known expression for the Purcell factor to the case of broad emitters, and to define strategies to optimize the performances of broad emitters-based single photon sources. Moreover, pure dephasing is shown to be able to restore lasing in presence of detuning, a further demonstration that decoherence can be seen as a fundamental resource in solid-state cavity quantum electrodynamics, offering appealing perspectives in the context of advanced nano-photonic devices.Comment: 10 pages, 7 figure

    Unique Minimal Liftings for Simplicial Polytopes

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    For a minimal inequality derived from a maximal lattice-free simplicial polytope in Rn\R^n, we investigate the region where minimal liftings are uniquely defined, and we characterize when this region covers Rn\R^n. We then use this characterization to show that a minimal inequality derived from a maximal lattice-free simplex in Rn\R^n with exactly one lattice point in the relative interior of each facet has a unique minimal lifting if and only if all the vertices of the simplex are lattice points.Comment: 15 page

    Wigner Measure Propagation and Conical Singularity for General Initial Data

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    We study the evolution of Wigner measures of a family of solutions of a Schr\"odinger equation with a scalar potential displaying a conical singularity. Under a genericity assumption, classical trajectories exist and are unique, thus the question of the propagation of Wigner measures along these trajectories becomes relevant. We prove the propagation for general initial data.Comment: 24 pages, 1 figur

    HI emission from the red giant Y CVn with the VLA and FAST

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    Imaging studies with the VLA have revealed HI emission associated with the extended circumstellar shells of red giants. We analyse the spectral map obtained on Y CVn, a J-type carbon star on the AGB. The HI line profiles can be interpreted with a model of a detached shell resulting from the interaction of a stellar outflow with the local interstellar medium. We reproduce the spectral map by introducing a distortion along a direction corresponding to the star's motion in space. We then use this fitting to simulate observations expected from the FAST radiotelescope, and discuss its potential for improving ourdescription of the outer regions of circumstellar shells.Comment: accepted for publication in RA
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