670 research outputs found

    Missing levels in correlated spectra

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    Complete spectroscopy (measurements of a complete sequence of consecutive levels) is often considered as a prerequisite to extract fluctuation properties of spectra. It is shown how this goal can be achieved even if only a fraction of levels are observed. The case of levels behaving as eigenvalues of random matrices, of current interest in nuclear physics, is worked out in detail.Comment: 14 pages and two figure

    Evaluation of Effective Astrophysical S factor for Non-Resonant Reactions

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    We derived analytic formulas of the effective S astrophysical S factor,S^eff for a non-resonant reaction of charged particles using a Taylor expension of the astrophysical S factor and a uniform approximation.The formulas will be able to generate generate more accurate approximation to S^eff than previous ones

    Structure of trajectories of complex matrix eigenvalues in the Hermitian-non-Hermitian transition

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    The statistical properties of trajectories of eigenvalues of Gaussian complex matrices whose Hermitian condition is progressively broken are investigated. It is shown how the ordering on the real axis of the real eigenvalues is reflected in the structure of the trajectories and also in the final distribution of the eigenvalues in the complex plane.Comment: 12 pages, 3 figure

    Causal Classical Theory of Radiation Damping

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    It is shown how initial conditions can be appropriately defined for the integration of Lorentz-Dirac equations of motion. The integration is performed \QTR{it}{forward} in time. The theory is applied to the case of the motion of an electron in an intense laser pulse, relevant to nonlinear Compton scattering.Comment: 8 pages, 2 figure

    Addendum: Attenuation of the intensity within a superdeformed band

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    We investigate a random matrix model [Phys. Rev. C {\bf 65} 024302 (2002] for the decay-out of a superdeformed band as a function of the parameters: Γ↓/ΓS\Gamma^\downarrow/\Gamma_S, ΓN/D\Gamma_N/D, ΓS/D\Gamma_S/D and Δ/D\Delta/D. Here Γ↓\Gamma^\downarrow is the spreading width for the mixing of an SD state ∣0>|0> with a normally deformed (ND) doorway state ∣d>|d>, ΓS\Gamma_S and ΓN\Gamma_N are the electromagnetic widths of the the SD and ND states respectively, DD is the mean level spacing of the compound ND states and Δ\Delta is the energy difference between ∣0>|0> and ∣d>|d>. The maximum possible effect of an order-chaos transition is inferred from analytical and numerical calculations of the decay intensity in the limiting cases for which the ND states obey Poisson and GOE statistics. Our results show that the sharp attenuation of the decay intensity cannot be explained solely by an order-chaos transition.Comment: 4 pages, 4 figures, submitted to Physical Review
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