5,904 research outputs found

    Reissner-Nordstrom-like solutions of the SU(2) Einstein-Yang/Mills (EYM) equations

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    In this paper we study a new type of solution of the spherically symmetric, Einstein-Yang/Mills (EYM) equations with SU(2) gauge group. These solutions are well-behaved in the far-field, and have a Reissner-Nordstrom type essential singularity at the origin. These solutions display some novel features which are not present in particle-like, or black-hole solutions. Any spherically symmetric solution to the EYM equations, defined in the far-field, is either a particle-like solution, a black-hole solution, or one of these RNL solutions.Comment: 5 pages, latex, no figures, Submitted to Comm. Math. Phys. January 15, 199

    Theory of transient spectroscopy of multiple quantum well structures

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    A theory of the transient spectroscopy of quantum well (QW) structures under a large applied bias is presented. An analytical model of the initial part of the transient current is proposed. The time constant of the transient current depends not only on the emission rate from the QWs, as is usually assumed, but also on the subsequent carrier transport across QWs. Numerical simulation was used to confirm the validity of the proposed model, and to study the transient current on a larger time scale. It is shown that the transient current is influenced by the nonuniform distribution of the electric field and related effects, which results in a step-like behavior of the current. A procedure of extraction of the QW emission time from the transient spectroscopy experiments is suggested.Comment: 5 pages, 4 figures, to be published in J. Appl. Phy

    Noiseless Collective Motion out of Noisy Chaos

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    We consider the effect of microscopic external noise on the collective motion of a globally coupled map in fully desynchronized states. Without the external noise a macroscopic variable shows high-dimensional chaos distinguishable from random motion. With the increase of external noise intensity, the collective motion is successively simplified. The number of effective degrees of freedom in the collective motion is found to decrease as logσ2-\log{\sigma^2} with the external noise variance σ2\sigma^2. It is shown how the microscopic noise can suppress the number of degrees of freedom at a macroscopic level.Comment: 9 pages RevTex file and 4 postscript figure

    The study of initial permeability temperature dependences for LiTiZn ferrite ceramics

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    Results of obtaining and analyzing the temperature dependences of initial permeability of ferrite ceramics are presented in the paper. It was shown that the level of the defective state of ferrite ceramics can be obtained from the value of two parameters [alpha] and [beta] of the phenomenological expression describing the experimental dependences. The results showed that the main criterion of the defect state is the parameter [beta]/[alpha], which is related to the elastic stresses in the material. An indicator of the structure perfection is also the value of the maximum of the initial permeability near the Curie temperature

    Scattering into Cones and Flux across Surfaces in Quantum Mechanics: a Pathwise Probabilistic Approach

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    We show how the scattering-into-cones and flux-across-surfaces theorems in Quantum Mechanics have very intuitive pathwise probabilistic versions based on some results by Carlen about large time behaviour of paths of Nelson diffusions. The quantum mechanical results can be then recovered by taking expectations in our pathwise statements.Comment: To appear in Journal of Mathematical Physic

    Three-body correlations in direct reactions: Example of 6^{6}Be populated in (p,n)(p,n) reaction

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    The 6^{6}Be continuum states were populated in the charge-exchange reaction 1^1H(6^{6}Li,6^{6}Be)nn collecting very high statistics data (5×106\sim 5 \times 10^6 events) on the three-body α\alpha+pp+pp correlations. The 6^{6}Be excitation energy region below 3\sim 3 MeV is considered, where the data are dominated by contributions from the 0+0^+ and 2+2^+ states. It is demonstrated how the high-statistics few-body correlation data can be used to extract detailed information on the reaction mechanism. Such a derivation is based on the fact that highly spin-aligned states are typically populated in the direct reactions.Comment: submitted to Physical Review

    Lyapunov Mode Dynamics in Hard-Disk Systems

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    The tangent dynamics of the Lyapunov modes and their dynamics as generated numerically - {\it the numerical dynamics} - is considered. We present a new phenomenological description of the numerical dynamical structure that accurately reproduces the experimental data for the quasi-one-dimensional hard-disk system, and shows that the Lyapunov mode numerical dynamics is linear and separate from the rest of the tangent space. Moreover, we propose a new, detailed structure for the Lyapunov mode tangent dynamics, which implies that the Lyapunov modes have well-defined (in)stability in either direction of time. We test this tangent dynamics and its derivative properties numerically with partial success. The phenomenological description involves a time-modal linear combination of all other Lyapunov modes on the same polarization branch and our proposed Lyapunov mode tangent dynamics is based upon the form of the tangent dynamics for the zero modes

    On the susceptibility function of piecewise expanding interval maps

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    We study the susceptibility function Psi(z) associated to the perturbation f_t=f+tX of a piecewise expanding interval map f. The analysis is based on a spectral description of transfer operators. It gives in particular sufficient conditions which guarantee that Psi(z) is holomorphic in a disc of larger than one. Although Psi(1) is the formal derivative of the SRB measure of f_t with respect to t, we present examples satisfying our conditions so that the SRB measure is not Lipschitz.*We propose a new version of Ruelle's conjectures.* In v2, we corrected a few minor mistakes and added Conjectures A-B and Remark 4.5. In v3, we corrected the perturbation (X(f(x)) instead of X(x)), in particular in the examples from Section 6. As a consequence, Psi(z) has a pole at z=1 for these examples.Comment: To appear Comm. Math. Phy

    Perturbation theory for self-gravitating gauge fields I: The odd-parity sector

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    A gauge and coordinate invariant perturbation theory for self-gravitating non-Abelian gauge fields is developed and used to analyze local uniqueness and linear stability properties of non-Abelian equilibrium configurations. It is shown that all admissible stationary odd-parity excitations of the static and spherically symmetric Einstein-Yang-Mills soliton and black hole solutions have total angular momentum number =1\ell = 1, and are characterized by non-vanishing asymptotic flux integrals. Local uniqueness results with respect to non-Abelian perturbations are also established for the Schwarzschild and the Reissner-Nordstr\"om solutions, which, in addition, are shown to be linearly stable under dynamical Einstein-Yang-Mills perturbations. Finally, unstable modes with =1\ell = 1 are also excluded for the static and spherically symmetric non-Abelian solitons and black holes.Comment: 23 pages, revtex, no figure
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