5,648 research outputs found

    Non-perturbative solutions in the electro-weak theory with tˉt\bar t t condensate and the tt-quark mass

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    We apply Bogoliubov compensation principle to the gauge electro-weak interaction to demonstrate a spontaneous generation of anomalous three-boson gauge invariant effective interaction. The non-trivial solution of compensation equations uniquely defines the form-factor of the anomalous interaction and parameters of the theory including value of gauge electro-weak coupling g(MW2)g(M_W^2) in satisfactory agreement with its experimental value. A possibility of spontaneous generation of effective four-fermion interaction of heavy quarks is also demonstrated. This interaction defines an equation for a scalar bound state of heavy quarks which serve as a substitute for the elementary scalar Higgs doublet. As a result we calculate the tt-quark mass mt=177GeVm_t\,=\,177\,GeV in satisfactory agreement with the experimental value. The results strongly support idea of tˉt\bar t\,t condensate as a source of the electro-weak symmetry breaking.Comment: 16 pages, 5 figures. arXiv admin note: substantial overlap with arXiv:1103.395

    CDF Wjj anomaly as a non-perturbative effect of the electro-weak interaction

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    The recently reported CDF excess at 120160GeV120\,-\, 160\,GeV in invariant mass distribution of jet pairs accompanying WW-boson is tentatively interpreted as a bound state of two WW decaying to quark-anti-quark pair. Non-perturbative effects of EW interaction obtained by application of Bogoliubov compensation approach lead to such bound state due to existence of anomalous three-boson gauge-invariant effective interaction. The application of this scheme gives satisfactory agreement with existing data without any adjusting parameter but the bound state mass 145GeV145\,GeV.Comment: 5 pages, 2 figure

    Local density of states at polygonal boundaries of d-wave superconductors

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    Besides the well-known existence of Andreev bound states, the zero-energy local density of states at the boundary of a d-wave superconductor strongly depends on the boundary geometry itself. In this work, we examine the influence of both a simple wedge-shaped boundary geometry and a more complicated polygonal or faceted boundary structure on the local density of states. For a wedge-shaped boundary geometry, we find oscillations of the zero-energy density of states in the corner of the wedge, depending on the opening angle of the wedge. Furthermore, we study the influence of a single Abrikosov vortex situated near a boundary, which is of either macroscopic or microscopic roughness.Comment: 10 pages, 11 figures; submitted to Phys. Rev.

    A Discrete Version of the Inverse Scattering Problem and the J-matrix Method

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    The problem of the Hamiltonian matrix in the oscillator and Laguerre basis construction from the S-matrix is treated in the context of the algebraic analogue of the Marchenko method.Comment: 11 pages. The Laguerre basis case is adde

    Theory of AC Josepson Effect in Superconducting Constrictions

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    We have developed a microscopic theory of ac Josephson effect in short ballistic superconducting constrictions with arbitrary electron transparency and in constrictions with diffusive electron transport. The theory is valid for arbitrary miscroscopic structure of the superconducting electrodes of the constriction. As applications of the theory we study smearing of the subgap current singularities by pair-breaking effects and also the structure of these singularities in the constrictions between the composite S/N electrodes with the proximity-induced gap in the normal layer.Comment: 11 pages, RevTex, 3 figures available on reques

    Boundary resistance in magnetic multilayers

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    Quasiclassical boundary conditions for electrochemical potentials at the interface between diffusive ferromagnetic and non-magnetic metals are derived for the first time. An expression for the boundary resistance accurately accounts for the momentum conservation law as well as essential gradients of the chemical potentials. Conditions are established at which spin-asymmetry of the boundary resistance has positive or negative sign. Dependence of the spin asymmetry and the absolute value of the boundary resistance on the exchange splitting of the conduction band opens up new possibility to estimate spin polarization of the conduction band of ferromagnetic metals. Consistency of the theory is checked on existing experimental data.Comment: 8 pages, 3 figures, designed using IOPART styl

    NN potentials from inverse scattering in the J-matrix approach

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    An approximate inverse scattering method [7,8] has been used to construct separable potentials with the Laguerre form factors. As an application, we invert the phase shifts of proton-proton in the 1S0^1S_0 and 3P23F2^3P_2-^3F_2 channels and neutron-proton in the 3S13D1^3S_1-^3D_1 channel elastic scattering. In the latter case the deuteron wave function of a realistic npnp potential was used as input.Comment: LaTex2e, 17 pages, 3 Postscript figures; corrected typo

    Josephson effect in superconducting constrictions with hybrid SF electrodes: peculiar properties determined by the misorientation of magnetizations

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    Josephson current in SFcFS junctions with arbitrary transparency of the constriction (c) is investigated. The emphasis is done on the analysis of the supercurrent dependencies on the misorientation angle θ\theta between the in-plane magnetizations of diffusive ferromagnetic layers (F). It is found that the current-phase relation I(ϕ)I(\phi) may be radically modified with the θ\theta variation: the harmonic I1sinϕI_{1}\sin \phi vanishes for definite value of θ\theta provided for identical orientation of the magnetizations (θ=0\theta =0) the junction is in the "π""\pi" state. The Josephson current may exhibit a nonmonotonic dependence on the misorientation angle both for realization of "0""0 " and "π""\pi " state at θ=0\theta =0. We also analyze the effect of exchange field induced enhancement of the critical current which may occur in definite range of θ\theta .Comment: 7 pages, 5 figures, submitted to JETP Letter

    Josephson π\pi-state in superconductor-Luttinger liquid hybrid systems

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    Josephson current through a Luttinger liquid (LL) under a magnetic field is theoretically studied. We derive an analytical expression of Josephson current for clean interfaces, by using quasiclassical Green's function and functional bosonization procedure. We show that critical currents can be renormalized by electron-electron interactions at perfect transparency when LL is adiabatically connected with superconductors. We also find that a generation of π\pi-state, due to spin-dependent energy shift in Andreev bound states (ABS), is prohibited even at zero temperature when the strength of repulsive interactions reaches some critical value. The suppression of π\pi-state is caused by the low energy fluctuations propagating in LL, and making the Zeeman splitting in ABS blurred.Comment: 5 pages, 4figure
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