2,593 research outputs found

    Compromising in Partition Function Form Games and Cooperation in Perfect Extensive Form

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    In this paper reasonable payoff intervals for players in a game in partition function form (p.f.f.game) are introduced and used to define the notion of compromisable p.f.f. game.For a compromisable p.f.f. game a compromise value is defined for which an axiomatic characterization is provided.Also a generic subclass of games in extensive form of perfect information without chance moves is introduced.For this class of perfect extensive form games there is a natural credible way to define a p.f.f. game if the players consider cooperation.It turns out that the p.f.f. games obtained in this way are compromisable.game theory

    A deformed QRPA formalism for single and two-neutrino double beta decay

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    We use a deformed QRPA formalism to describe simultaneously the energy distributions of the single beta Gamow-Teller strength and the two-neutrino double beta decay matrix elements. Calculations are performed in a series of double beta decay partners with A = 48, 76, 82, 96, 100, 116, 128, 130, 136 and 150, using deformed Woods-Saxon potentials and deformed Skyrme Hartree-Fock mean fields. The formalism includes a quasiparticle deformed basis and residual spin-isospin forces in the particle-hole and particle-particle channels. We discuss the sensitivity of the parent and daughter Gamow-Teller strength distributions in single beta decay, as well as the sensitivity of the double beta decay matrix elements to the deformed mean field and to the residual interactions. Nuclear deformation is found to be a mechanism of suppression of the two-neutrino double beta decay. The double beta decay matrix elements are found to have maximum values for about equal deformations of parent and daughter nuclei. They decrease rapidly when differences in deformations increase. We remark the importance of a proper simultaneous description of both double beta decay and single Gamow-Teller strength distributions. Finally, we conclude that for further progress in the field it would be useful to improve and complete the experimental information on the studied Gamow-Teller strengths and nuclear deformations.Comment: 33 pages, 19 figures. To be published in Phys. Rev.

    Role of three-body interactions in formation of bulk viscosity in liquid argon

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    With the aim of locating the origin of discrepancy between experimental and computer simulation results on bulk viscosity of liquid argon, a molecular dynamic simulation of argon interacting via ab initio pair potential and triple-dipole three-body potential has been undertaken. Bulk viscosity, obtained using Green-Kubo formula, is different from the values obtained from modeling argon using Lennard-Jones potential, the former being closer to the experimental data. The conclusion is made that many-body inter-atomic interaction plays a significant role in formation of bulk viscosity.Comment: 4 pages, 3 figure

    Fuzzy Clan Games and Bi-monotonic Allocation Rules

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    Clan game;Big boss game;Core;Decision making;Fuzzy coalition;Fuzzy game;Monotonic allocation rule

    Phase transitions in systems with two species of molecular motors

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    Systems with two species of active molecular motors moving on (cytoskeletal) filaments into opposite directions are studied theoretically using driven lattice gas models. The motors can unbind from and rebind to the filaments. Two motors are more likely to bind on adjacent filament sites if they belong to the same species. These systems exhibit (i) Continuous phase transitions towards states with spontaneously broken symmetry, where one motor species is largely excluded from the filament, (ii) Hysteresis of the total current upon varying the relative concentrations of the two motor species, and (iii) Coexistence of traffic lanes with opposite directionality in multi-filament systems. These theoretical predictions should be experimentally accessible.Comment: 7 pages, 4 figures, epl style (.cls-file included), to appear in Europhys. Lett. (http://www.edpsciences.org/epl

    Stepwise Projection: Toward Brane Setups for Generic Orbifold Singularities

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    The construction of brane setups for the exceptional series E6,E7,E8 of SU(2) orbifolds remains an ever-haunting conundrum. Motivated by techniques in some works by Muto on non-Abelian SU(3) orbifolds, we here provide an algorithmic outlook, a method which we call stepwise projection, that may shed some light on this puzzle. We exemplify this method, consisting of transformation rules for obtaining complex quivers and brane setups from more elementary ones, to the cases of the D-series and E6 finite subgroups of SU(2). Furthermore, we demonstrate the generality of the stepwise procedure by appealing to Frobenius' theory of Induced Representations. Our algorithm suggests the existence of generalisations of the orientifold plane in string theory.Comment: 22 pages, 3 figure

    Spin-filter tunnel junction with matched Fermi surfaces

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    Efficient injection of spin-polarized current into a semiconductor is a basic prerequisite for building semiconductor-based spintronic devices. Here, we use inelastic electron tunneling spectroscopy to show that the efficiency of spin-filter-type spin injectors is limited by spin scattering of the tunneling electrons. By matching the Fermi-surface shapes of the current injection source and target electrode material, spin injection efficiency can be significantly increased in epitaxial ferromagnetic insulator tunnel junctions. Our results demonstrate that not only structural but also Fermi-surface matching is important to suppress scattering processes in spintronic devices.Comment: 5 pages, 4 figure

    Shell Model Study of the Double Beta Decays of 76^{76}Ge, 82^{82}Se and 136^{136}Xe

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    The lifetimes for the double beta decays of 76^{76}Ge, 82^{82}Se and 136^{136}Xe are calculated using very large shell model spaces. The two neutrino matrix elements obtained are in good agreement with the present experimental data. For <1<1 eV we predict the following upper bounds to the half-lives for the neutrinoless mode: T1/2(0Îœ)(Ge)>1.85 1025yr.T^{(0\nu)}_{1/2}(Ge) > 1.85\,10^{25} yr., T1/2(0Îœ)(Se)>2.36 1024yr.T^{(0\nu)}_{1/2}(Se) > 2.36\,10^{24} yr. and T1/2(0Îœ)(Xe)>1.21 1025yrT^{(0\nu)}_{1/2}(Xe) > 1.21\,10^{25} yr. These results are the first from a new generation of Shell Model calculations reaching O(108^{8}) dimensions

    Effect of doping and oxygen vacancies on the octahedral tilt transitions in the BaCeO3 perovskite

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    We present a systematic study of the effect of Y doping and hydration level on the structural transformations of BaCeO3 based on anelastic spectroscopy experiments. The temperature of the intermediate transformation between rhombohedral and orthorhombic Imma phases rises with increasing the molar fraction x of Y roughly as (500 K)x in the hydrated state, and is depressed of more than twice that amount after complete dehydration. This is explained in terms of the effect of doping on the average (Ce/Y)-O and Ba-O bond lengths, and of lattice relaxation from O vacancies. The different behavior of the transition to the lower temperature Pnma orthorhombic phase is tentatively explained in terms of progressive flattening of the effective shape of the OH ion and ordering of the O vacancies during cooling.Comment: 8 pages, 5 figure
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