8,484 research outputs found

    Quantal Extension of Mean-Field Dynamics

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    A method is presented for numerical implementation of the extended TDHF theory in which two-body correlations beyond the mean-field approximation are incorporated in the form of a quantal collision term. The method is tested in a model problem in which the exact solution can be obtained numerically. Whereas the usual TDHF fails to reproduce the long time evolution, a very good agreement is found between the extended TDHF and the exact solution.Comment: 22 Latex pages including 7 figure

    Legal origin and the evolution of environmental quality

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    We extend the empirical literature on the environmental Kuznets curve (EKC) by showing the legal origin matters for the evolution of environmental quality. Using observations of ambient sulfur dioxide levels, we find that the EKC for French and British legal origin countries diverge as incomes rise, with the EKC for French legal origin countries lying significantly below that for countries of British legal origin. This finding is robust to the inclusion of proxies for democracy and corruption, the institutional variables emphasized in the current EKC literature. Our results are consistent with the idea that the British common law tradition places a greater emphasis on private relative to collective property rights.Environmental quality, institutions, legal origin. economic development, evironmental Kuznets curve

    Nucleon exchange in heavy-ion collisions within stochastic mean-field approach

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    Nucleon exchange mechanism is investigated in deep-inelastic symmetric heavy-ion collisions in the basis of the Stochastic Mean-Field approach. By extending the previous work to off-central collisions, analytical expression is deduced for diffusion coefficient of nucleon exchange mechanism. Numerical calculations are carried out for 40{}^{40}Ca + 40{}^{40}Ca and 90{}^{90}Zr + 90{}^{90}Zr systems and the results are compared with the phenomenological nucleon exchange model. Also, calculations are compared with the available experimental results of deep-inelastic collisions between calcium nuclei.Comment: 8 pages, 7 figure

    Ultrafast dynamics of finite Hubbard clusters - a stochastic mean-field approach

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    Finite lattice models are a prototype for strongly correlated quantum systems and capture essential properties of condensed matter systems. With the dramatic progress in ultracold atoms in optical lattices, finite fermionic Hubbard systems have become directly accessible in experiments, including their ultrafast dynamics far from equilibrium. Here, we present a theoretical approach that is able to treat these dynamics in any dimension and fully includes inhomogeneity effects. The method consists in stochastic sampling of mean-field trajectories and is found to be more accurate and efficient than current nonequilibrium Green functions approaches. This is demonstrated for Hubbard clusters with up to 512 particles in one, two and three dimensions

    Superfluid fission dynamics with microscopic approaches

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    Recent progresses in the description of the latter stage of nuclear fission are reported. Dynamical effects during the descent of the potential towards scission and in the formation of the fission fragments are studied with the time-dependent Hartree-Fock approach with dynamical pairing correlations at the BCS level. In particular, this approach is used to compute the final kinetic energy of the fission fragments. Comparison with experimental data on the fission of 258Fm are made.Comment: Proceeding of the "International Conference on Nuclear Structure and Related Topics" (NSRT15

    Quantal description of nucleon exchange in stochastic mean-field approach

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    Nucleon exchange mechanism is investigated in central collisions of symmetric heavy-ions in the basis of the stochastic mean-field approach. Quantal diffusion coefficients for nucleon exchange are calculated by including non-Markovian effects and shell structure. Variances of fragment mass distributions are calculated in central collisions of 40{}^{40}Ca + 40{}^{40}Ca, 48{}^{48}Ca + 48{}^{48}Ca and 56{}^{56}Ni + 56{}^{56}Ni systems
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