1,283 research outputs found
Multifragmentation calculated with relativistic force
A saturating hamiltonian is presented in a relativistically covariant
formalism. The interaction is described by scalar and vector mesons, with
coupling strengths adjusted to the nuclear matter. No explicit density depe
ndence is assumed. The hamiltonian is applied in a QMD calculation to determine
the fragment distribution in O + Br collision at different energies (50 -- 200
MeV/u) to test the applicability of the model at low energies. The results are
compared with experiment and with previous non-relativistic calculations.
PACS: 25.70Mn, 25.75.+rComment: 23 pages, latex, with 10 PS figures, available at
http://www.gsi.de/~papp
Instabilities in Nuclei
The evolution of dynamical perturbations is examined in nuclear
multifragmentation in the frame of Vlasov equation. Both plane wave and bubble
type of perturbations are investigated in the presence of surface (Yukawa)
forces. An energy condition is given for the allowed type of instabilities and
the time scale of the exponential growth of the instabilities is calculated.
The results are compared to the mechanical spinodal region predictions. PACS:
25.70 MnComment: 22 pages, latex, with 5 PS figures, available at
http://www.gsi.de/~papp
Spectral Determinant Method for Interacting N-body Systems Including Impurities
A general expression for the Green's function of a system of particles
(bosons/fermions) interacting by contact potentials, including impurities with
Dirac-delta type potentials is derived. In one dimension for bosons from
our {\it spectral determinant method} the numerically calculated energy levels
agree very well with those obtained from the exact Bethe ansatz solutions while
they are an order of magnitude more accurate than those found by direct
diagonalization. For N=2 bosons the agreement is shown analytically. In the
case of N=2 interacting bosons and one impurity, the energy levels are
calculated numerically from the spectral determinant of the system. The
spectral determinant method is applied to an interacting fermion system
including an impurity to calculate the persistent current at the presence of
magnetic field.Comment: revtex, 19 pages, 4 figure
AN ELECTION ALGORITHM FOR A MULTIPROCESSOR CONTROLLED DIGITAL EXCHANGE
A multiprocessor controlled distributed digital exchange is studied in case of some failure types. The recovery from a failure is based on temporary suspension of the normal operation and the active processors elect a coordinator controlling the reconfiguration of the system. The algorithm developed for such an election is used at initial (cold) start of the system and in case of reintroducing one or more processors repaired as well. The failure environment is given and the assertions are proved verifying the algorithm described
Au+Au central collisions at 150, 250 and 400 AMeV energies in QMD with relativistic forces
An extensive comparison of the recent experimental data published by the FOPI
collaboration at GSI with the results of a relativistically covariant
formulation of a QMD code is presented. For most of the quantities we find
agreement with the experimental results showing that the derived force has a
reasonable momentum dependence.Comment: 33 pages with 18 EPSF figures included. Final version to appear in
Nucl. Phys.
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