2,026 research outputs found

    Effective Free Energy for Individual Dynamics

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    Physics and economics are two disciplines that share the common challenge of linking microscopic and macroscopic behaviors. However, while physics is based on collective dynamics, economics is based on individual choices. This conceptual difference is one of the main obstacles one has to overcome in order to characterize analytically economic models. In this paper, we build both on statistical mechanics and the game theory notion of Potential Function to introduce a rigorous generalization of the physicist's free energy, which includes individual dynamics. Our approach paves the way to analytical treatments of a wide range of socio-economic models and might bring new insights into them. As first examples, we derive solutions for a congestion model and a residential segregation model.Comment: 8 pages, 2 figures, presented at the ECCS'10 conferenc

    Irreducible decomposition for tensor prodect representations of Jordanian quantum algebras

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    Tensor products of irreducible representations of the Jordanian quantum algebras U_h(sl(2)) and U_h(su(1,1)) are considered. For both the highest weight finite dimensional representations of U_h(sl(2)) and lowest weight infinite dimensional ones of U_h(su(1,1)), it is shown that tensor product representations are reducible and that the decomposition rules to irreducible representations are exactly the same as those of corresponding Lie algebras.Comment: LaTeX, 14pages, no figur

    The Dirac Oscillator. A relativistic version of the Jaynes--Cummings model

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    The dynamics of wave packets in a relativistic Dirac oscillator is compared to that of the Jaynes-Cummings model. The strong spin-orbit coupling of the Dirac oscillator produces the entanglement of the spin with the orbital motion similar to what is observed in the model of quantum optics. The collapses and revivals of the spin which result extend to a relativistic theory our previous findings on nonrelativistic oscillator where they were known under the name of `spin-orbit pendulum'. There are important relativistic effects (lack of periodicity, zitterbewegung, negative energy states). Many of them disappear after a Foldy-Wouthuysen transformation.Comment: LaTeX2e, uses IOP style files (included), 14 pages, 9 separate postscript figure

    Kink propagation in a two-dimensional curved Josephson junction

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    We consider the propagation of sine-Gordon kinks in a planar curved strip as a model of nonlinear wave propagation in curved wave guides. The homogeneous Neumann transverse boundary conditions, in the curvilinear coordinates, allow to assume a homogeneous kink solution. Using a simple collective variable approach based on the kink coordinate, we show that curved regions act as potential barriers for the wave and determine the threshold velocity for the kink to cross. The analysis is confirmed by numerical solution of the 2D sine-Gordon equation.Comment: 8 pages, 4 figures (2 in color

    Beyond Prejudice as Simple Antipathy: Hostile and Benevolent Sexism Across Cultures

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    The authors argue that complementary hostile and benevolent componen:s of sexism exist ac ro.ss cultures. Male dominance creates hostile sexism (HS). but men's dependence on women fosters benevolent sexism (BS)-subjectively positive attitudes that put women on a pedestal but reinforce their subordination. Research with 15,000 men and women in 19 nations showed that (a) HS and BS are coherenl constructs th at correlate positively across nations, but (b) HS predicts the ascription of negative and BS the ascription of positive traits to women, (c) relative to men, women are more likely to reject HS than BS. especially when overall levels of sexism in a culture are high, and (d) national averages on BS and HS predict gender inequal ity across nations. These results challenge prevailing notions of prejudice as an antipathy in that BS (an affectionate, patronizing ideology) reflects inequality and is a cross-culturally pervasive complement to HS

    On some nonlinear extensions of the angular momentum algebra

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    Deformations of the Lie algebras so(4), so(3,1), and e(3) that leave their so(3) subalgebra undeformed and preserve their coset structure are considered. It is shown that such deformed algebras are associative for any choice of the deformation parameters. Their Casimir operators are obtained and some of their unitary irreducible representations are constructed. For vanishing deformation, the latter go over into those of the corresponding Lie algebras that contain each of the so(3) unitary irreducible representations at most once. It is also proved that similar deformations of the Lie algebras su(3), sl(3,R), and of the semidirect sum of an abelian algebra t(5) and so(3) do not lead to associative algebras.Comment: 22 pages, plain TeX + preprint.sty, no figures, to appear in J.Phys.

    Nonlinear collective nuclear motion

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    For each real number Λ\Lambda a Lie algebra of nonlinear vector fields on three dimensional Euclidean space is reported. Although each algebra is mathematically isomorphic to gl(3,R)gl(3,{\bf R}), only the Λ=0\Lambda=0 vector fields correspond to the usual generators of the general linear group. The Λ<0\Lambda < 0 vector fields integrate to a nonstandard action of the general linear group; the Λ>0\Lambda >0 case integrates to a local Lie semigroup. For each Λ\Lambda, a family of surfaces is identified that is invariant with respect to the group or semigroup action. For positive Λ\Lambda the surfaces describe fissioning nuclei with a neck, while negative Λ\Lambda surfaces correspond to exotic bubble nuclei. Collective models for neck and bubble nuclei are given by irreducible unitary representations of a fifteen dimensional semidirect sum spectrum generating algebra gcm(3)gcm(3) spanned by its nonlinear gl(3,R)gl(3,{\bf R}) subalgebra plus an abelian nonlinear inertia tensor subalgebra.Comment: 13 pages plus two figures(available by fax from authors by request

    Multifrequency Photo-polarimetric WEBT Observation Campaign on the Blazar S5 0716+714: Source Microvariability and Search for Characteristic Timescales

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    Here we report on the results of the WEBT photo-polarimetric campaign targeting the blazar S5~0716+71, organized in March 2014 to monitor the source simultaneously in BVRI and near IR filters. The campaign resulted in an unprecedented dataset spanning 110\sim 110\,h of nearly continuous, multi-band observations, including two sets of densely sampled polarimetric data mainly in R filter. During the campaign, the source displayed pronounced variability with peak-to-peak variations of about 30%30\% and "bluer-when-brighter" spectral evolution, consisting of a day-timescale modulation with superimposed hourlong microflares characterized by 0.1\sim 0.1\,mag flux changes. We performed an in-depth search for quasi-periodicities in the source light curve; hints for the presence of oscillations on timescales of 3\sim 3\,h and 5\sim 5\,h do not represent highly significant departures from a pure red-noise power spectrum. We observed that, at a certain configuration of the optical polarization angle relative to the positional angle of the innermost radio jet in the source, changes in the polarization degree led the total flux variability by about 2\,h; meanwhile, when the relative configuration of the polarization and jet angles altered, no such lag could be noted. The microflaring events, when analyzed as separate pulse emission components, were found to be characterized by a very high polarization degree (>30%> 30\%) and polarization angles which differed substantially from the polarization angle of the underlying background component, or from the radio jet positional angle. We discuss the results in the general context of blazar emission and energy dissipation models.Comment: 16 pages, 17 Figures; ApJ accepte

    SU(3) realization of the rigid asymmetric rotor within the IBM

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    It is shown that the spectrum of the asymmetric rotor can be realized quantum mechanically in terms of a system of interacting bosons. This is achieved in the SU(3) limit of the interacting boson model by considering higher-order interactions between the bosons. The spectrum corresponds to that of a rigid asymmetric rotor in the limit of infinite boson number.Comment: 9 pages, 2 figures, LaTeX, epsfi
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