519 research outputs found

    Jordanian Quantum Algebra Uh(sl(N)){\cal U}_{\sf h}(sl(N)) via Contraction Method and Mapping

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    Using the contraction procedure introduced by us in Ref. \cite{ACC2}, we construct, in the first part of the present letter, the Jordanian quantum Hopf algebra Uh(sl(3)){\cal U}_{\sf h}(sl(3)) which has a remarkably simple coalgebraic structure and contains the Jordanian Hopf algebra Uh(sl(2)){\cal U}_{\sf h}(sl(2)), obtained by Ohn, as a subalgebra. A nonlinear map between Uh(sl(3)){\cal U}_{\sf h}(sl(3)) and the classical sl(3)sl(3) algebra is then established. In the second part, we give the higher dimensional Jordanian algebras Uh(sl(N)){\cal U}_{\sf h}(sl(N)) for all NN. The Universal Rh{\cal R}_{\sf h}-matrix of Uh(sl(N)){\cal U}_{\sf h} (sl(N)) is also given.Comment: 17 pages, Late

    Theory of NMR as a local probe for the electronic structure in the mixed state of the high-TcT_c cuprates

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    We argue that nuclear magnetic resonance experiments are a site-sensitive probe for the electronic spectrum in the mixed state of the high-TcT_c cuprates. Within a spin-fermion model, we show that the Doppler-shifted electronic spectrum arising from the circulating supercurrent changes the low-frequency behavior of the imaginary part of the spin-susceptibility. For a hexagonal vortex lattice, we predict that these changes lead to {\it (a)} a unique dependence of the 63^{63}Cu spin lattice relaxation rate, 1/T11/T_1, on resonance frequency, and {\it (b)} a temperature dependence of T1T_1 which varies with frequency. We propose a nuclear quadrupole experiment to study the effects of a uniform supercurrent on the electronic structure and predict that T1T_1 varies with the direction of the supercurrent.Comment: RevTex, 5 pages, 3 figures embedded in the tex

    Magnetization and specific heat of TbFe3(BO3)4: Experiment and crystal field calculations

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    We have studied the thermodynamic properties of single-crystalline TbFe3(BO3)4. Magnetization measurements have been carried out as a function of magnetic field (up to 50 T) and temperature up to 350K with the magnetic field both parallel and perpendicular to the trigonal c-axis of the crystal. The specific heat has been measured in the temperature range 2-300K with a magnetic field up to 9 T applied parallel to the c-axis. The data indicate a structural phase transition at 192 K and antiferromagnetic spin ordering at 40 K. A Schottky anomaly is present in the specific heat data around 20 K, arising due to two low-lying energy levels of the Tb3+ ions being split by f-d coupling. Below TN magnetic fields parallel to the c-axis drive a spin-flop phase transition, which is associated with a large magnetization jump. The highly anisotropic character of the magnetic susceptibility is ascribed mainly to the Ising-like behavior of the Tb3+ ions in the trigonal crystal field. We describe our results in the framework of an unified approach which is based on mean-field approximation and crystal-field calculations.Comment: 10 pages, 10 figures, 20 references, accepted by Phys. Rev.

    Bicovariant Differential Geometry of the Quantum Group SLh(2)SL_h(2)

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    There are only two quantum group structures on the space of two by two unimodular matrices, these are the SLq(2)SL_q(2) and the SLh(2)SL_h(2) [9-13] quantum groups. One can not construct a differential geometry on SLq(2) SL_q(2), which at the same time is bicovariant, has three generators, and satisfies the Liebnitz rule. We show that such a differential geometry exists for the quantum group SLh(2)SL_h(2) and derive all of its properties

    Efficiency of multidisciplinary rehabilitation of patients with breast cancer

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    The purpose of the study is evaluating the effectiveness of an interdisciplinary integrated approach in the rehabilitation of patients with breast cancer.Цель исследования – оценить эффективность междисциплинарного комплексного подхода в реабилитации пациентов с раком молочной железы

    Deformed Minkowski spaces: clasification and properties

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    Using general but simple covariance arguments, we classify the `quantum' Minkowski spaces for dimensionless deformation parameters. This requires a previous analysis of the associated Lorentz groups, which reproduces a previous classification by Woronowicz and Zakrzewski. As a consequence of the unified analysis presented, we give the commutation properties, the deformed (and central) length element and the metric tensor for the different spacetime algebras.Comment: Some comments/misprints have been added/corrected, to appear in Journal of Physics A (1996

    Acoustic Power Absorption and its Relation with Vector Magnetic Field of a Sunspot

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    The distribution of acoustic power over sunspots shows an enhanced absorption near the umbra--penumbra boundary. Earlier studies revealed that the region of enhanced absorption coincides with the region of strongest transverse potential field. The aim of this paper is to (i) utilize the high-resolution vector magnetograms derived using Hinode SOT/SP observations and study the relationship between the vector magnetic field and power absorption and (ii) study the variation of power absorption in sunspot penumbrae due to the presence of spine-like radial structures. It is found that (i) both potential and observed transverse fields peak at a similar radial distance from the center of the sunspot, and (ii) the magnitude of the transverse field, derived from Hinode observations, is much larger than the potential transverse field derived from SOHO/MDI longitudinal field observations. In the penumbra, the radial structures called spines (intra-spines) have stronger (weaker) field strength and are more vertical (horizontal). The absorption of acoustic power in the spine and intra-spine shows different behaviour with the absorption being larger in the spine as compared to the intra-spine.Comment: 18 pages, 7 figures, In Press Solar Physics, Topical Issue on Helio-and-Astroseismolog
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