39,400 research outputs found

    [Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)]

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    We study the Hopf algebra structure and the highest weight representation of a multiparameter version of Uqgl(2)U_{q}gl(2). The commutation relations as well as other Hopf algebra maps are explicitly given. We show that the multiparameter universal R{\cal R} matrix can be constructed directly as a quantum double intertwiner, without using Reshetikhin's transformation. An interesting feature automatically appears in the representation theory: it can be divided into two types, one for generic qq, the other for qq being a root of unity. When applying the representation theory to the multiparameter universal R{\cal R} matrix, the so called standard and nonstandard colored solutions R(μ,ν;μ′,ν′)R(\mu,\nu; {\mu}', {\nu}') of the Yang-Baxter equation is obtained.Comment: [14]pages, latex, no figure

    Y(so(5)) symmtry of the nonlinear Schro¨\ddot{o}dinger model with four-cmponents

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    The quantum nonlinear Schro¨\ddot{o}dinger(NLS) model with four-component fermions exhibits a Y(so(5))Y(so(5)) symmetry when considered on an infintite interval. The constructed generators of Yangian are proved to satisfy the Drinfel'd formula and furthermore, the RTTRTT relation with the general form of rational R-matrix given by Yang-Baxterization associated with so(5)so(5) algebraic structure.Comment: 10 pages, no figure

    Variational formulas of higher order mean curvatures

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    In this paper, we establish the first variational formula and its Euler-Lagrange equation for the total 2p2p-th mean curvature functional M2p\mathcal {M}_{2p} of a submanifold MnM^n in a general Riemannian manifold Nn+mN^{n+m} for p=0,1,...,[n2]p=0,1,...,[\frac{n}{2}]. As an example, we prove that closed complex submanifolds in complex projective spaces are critical points of the functional M2p\mathcal {M}_{2p}, called relatively 2p2p-minimal submanifolds, for all pp. At last, we discuss the relations between relatively 2p2p-minimal submanifolds and austere submanifolds in real space forms, as well as a special variational problem.Comment: 13 pages, to appear in SCIENCE CHINA Mathematics 201

    Semiclassical approach to the quantum Loschmidt echo in deep quantum regions: from validity to breakdown

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    Semiclassical results are usually expected to be valid in the semiclassical regime. An interesting question is, in models in which appropriate effective Planck constants can be introduced, to what extent will a semiclassical prediction stay valid when the effective Planck constant is increased? In this paper, we numerically study this problem, focusing on semiclassical predictions for the decay of the quantum Loschmidt echo in deep quantum regions. Our numerical simulations, carried out in the chaotic regime in the sawtooth model and in the kicked rotator model and also in the critical region of a 1D Ising chain in transverse field, show that the semiclassical predictions may work even in deep quantum regions, in particularly, for perturbation strength in the so-called Fermi-Golden-rule regime.Comment: 8 pages, 10 figures. Published versio
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