18,451 research outputs found

    BCS theory of nodal superconductors

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    This course has a dual purpose. First we review the successes of the weak-coupling BCS theory in describing new classes of superconductors discovered since 1979. They include the heavy-fermion superconductors, high-Tc cuprate superconductors, organic superconductors, Sr2RuO4, etc. Second, we present the quasiclassical approximation introduced by Volovik, which we extend to describe the thermodynamics and the thermal conductivity of the vortex state in nodal superconductors. This approach provides the most powerful tool to identify the symmetry of the energy gap function Delta(k) in these new superconductors.Comment: 31 pages, 33 figure

    New World of Gossamer Superconductivity

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    Since the discovery of the high-Tc_{c} cuprate superconductor La2−x_{2-x}BaCuO4_{4} in 1986 by Bednorz and M\"{u}ller, controversy regarding the nature or origin of this remarkable superconductivity has continued. However, d-wave superconductivity in the hole-doped cuprates, arising due to the anti-paramagnon exchange, was established around 1994. More recently we have shown that the mean field theory, like the BCS theory of superconductivity and Landau's Fermi liquid theory are adequate to describe the cuprates. The keys for this development are the facts that a)the pseudogap phase is d-wave density wave (dDW) and that the high-Tc_{c} cuprate superconductivity is gossamer (i.e. it exists in the presence of dDW).Comment: 6 pages, 4 figure

    On the linearization of the generalized Ermakov systems

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    A linearization procedure is proposed for Ermakov systems with frequency depending on dynamic variables. The procedure applies to a wide class of generalized Ermakov systems which are linearizable in a manner similar to that applicable to usual Ermakov systems. The Kepler--Ermakov systems belong into this category but others, more generic, systems are also included

    Generalized Hamiltonian structures for Ermakov systems

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    We construct Poisson structures for Ermakov systems, using the Ermakov invariant as the Hamiltonian. Two classes of Poisson structures are obtained, one of them degenerate, in which case we derive the Casimir functions. In some situations, the existence of Casimir functions can give rise to superintegrable Ermakov systems. Finally, we characterize the cases where linearization of the equations of motion is possible

    Computer Code System V. S. O. P. (99/11) Update 2011 of V.S.O.P(99)-Version 2009 CODE MANUAL

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    V.S.O.P. is a computer code system for the comprehensive numerical simulation of the physics of thermal reactors. The application of the code implies processing of cross sections, the set-up of the reactor and of the fuel element, neutron spectrum evaluation, neutron diffusion calculation, fuel burnup, fuel shuffling, reactor control, and thermal hydraulics of steady states and transients. The neutronics calculations can be performed in up to three dimensions. Thermal hydraulics is restricted to gas-cooled reactors in two spatial dimensions. Evaluation of fuel cycle costs over the reactor life time is made using the present worth method. A broad description of the features of the code has been published in Ref. /1/
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