45 research outputs found

    Self-consistent calculation of nuclear photoabsorption cross section: Finite amplitude method with Skyrme functionals in the three-dimensional real space

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    The finite amplitude method (FAM), which we have recently proposed (T. Nakatsukasa, T. Inakura, and K. Yabana, Phys. Rev. C 76, 024318 (2007)), simplifies significantly the fully self-consistent RPA calculation. Employing the FAM, we are conducting systematic, fully self-consistent response calculations for a wide mass region. This paper is intended to present a computational scheme to be used in the systematic investigation and to show the performance of the FAM for a realistic Skyrme energy functional. We implemented the method in the mixed representation in which the forward and backward RPA amplitudes are represented by indices of single-particle orbitals for occupied states and the spatial grid points for unoccupied states. We solve the linear response equation for a given frequency. The equation is a linear algebraic problem with a sparse non-hermitian matrix, which is solved with an iterative method. We show results of the dipole response for selected spherical and deformed nuclei. The peak energies of the giant dipole resonance agree well with measurements for heavy nuclei, while they are systematically underestimated for light nuclei. We also discuss the width of the giant dipole resonance in the fully self-consistent RPA calculation.Comment: 11 pages, 10 figure

    Systems of Hess-Appel'rot Type and Zhukovskii Property

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    We start with a review of a class of systems with invariant relations, so called {\it systems of Hess--Appel'rot type} that generalizes the classical Hess--Appel'rot rigid body case. The systems of Hess-Appel'rot type carry an interesting combination of both integrable and non-integrable properties. Further, following integrable line, we study partial reductions and systems having what we call the {\it Zhukovskii property}: these are Hamiltonian systems with invariant relations, such that partially reduced systems are completely integrable. We prove that the Zhukovskii property is a quite general characteristic of systems of Hess-Appel'rote type. The partial reduction neglects the most interesting and challenging part of the dynamics of the systems of Hess-Appel'rot type - the non-integrable part, some analysis of which may be seen as a reconstruction problem. We show that an integrable system, the magnetic pendulum on the oriented Grassmannian Gr+(4,2)Gr^+(4,2) has natural interpretation within Zhukovskii property and it is equivalent to a partial reduction of certain system of Hess-Appel'rot type. We perform a classical and an algebro-geometric integration of the system, as an example of an isoholomorphic system. The paper presents a lot of examples of systems of Hess-Appel'rot type, giving an additional argument in favor of further study of this class of systems.Comment: 42 page

    Mutual heavy ion dissociation in peripheral collisions at ultrarelativistic energies

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    We study mutual dissociation of heavy nuclei in peripheral collisions at ultrarelativistic energies. Earlier this process was proposed for beam luminosity monitoring via simultaneous registration of forward and backward neutrons in zero degree calorimeters at Relativistic Heavy Ion Collider. Electromagnetic dissociation of heavy ions is considered in the framework of the Weizsacker-Williams method and simulated by the RELDIS code. Photoneutron cross sections measured in different experiments and calculated by the GNASH code are used as input for the calculations of dissociation cross sections. The difference in results obtained with different inputs provides a realistic estimation for the systematic uncertainty of the luminosity monitoring method. Contribution to simultaneous neutron emission due to grazing nuclear interactions is calculated within the abrasion model. Good description of CERN SPS experimental data on Au and Pb dissociation gives confidence in predictive power of the model for AuAu and PbPb collisions at RHIC and LHC.Comment: 46 pages with 7 tables and 13 figures, numerical integration accuracy improved, next-to-leading-order corrections include

    Estudo multicêntrico comparativo de quatro diferentes tipos de sensores: atividade, acelerômetro, temperatura e período de pré-ejeçao

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    Recentemente diferentes princípios têm sido utilizados para estimular o coraçao na tentativa de recuperar o débito cardíaco. Neste estudo multicêntrico, foram comparadas as respostas à estimulaçao por 4 tipos de sensores, sendo 3 tipos de resposta de alça aberta (atividade física, acelerômetro e temperatura venosa central) implantados em 30 (SSIR-8 e DDDR-22), 9 (SSIR-5 -e DDDR-4) e 12 (SSIR) pacientes respectivamente. Um outro sensor do tipo alça fechada, sensível às variaçoes do sistema nervoso autônomo, foi implantado em 57 pacientes, todos no modo DDDR. Os resultados obtidos durante a realizaçao de atividade física diária, de teste ergométrico e de Holter de 24 horas foram comparados, sendo possível observar uma maior fidelidade na curva de resposta de freqüência frente a atividade física, nos pacientes submetidos à estimulaçao de alça fechada
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