361 research outputs found
Giant monopole resonance and nuclear compression modulus for 40Ca and 16O
Using a collective potential derived on the basis of the Generator Coordinate
Method with Skyrme interactions we obtain values for the compression modulus of
40Ca which are in good agreement with a recently obtained experimental value.
Calculated values for the compression modulus for 16O are also given. The
procedure involved in the derivation of the collective potential is briefly
reviewed and discussed.Comment: 14 pages, no figures, two tables, REVTE
Population Dynamics in the Penna Model
We build upon the recent steady-state Penna model solution, Phys.Rev.Lett.
89, 288103 (2002), to study the population dynamics within the Penna model. We
show, that any perturbation to the population can be broken into a collection
of modes each of which decay exponentially with its respective time constant.
The long time behaviour of population is therefore likely to be dominated by
the modes with the largest time constants. We confirm our analytical approach
with simulation data.Comment: 6 figure
Fermion Pairing Dynamics in the Relativistic Scalar Plasma
Using many-body techniques we obtain the time-dependent Gaussian
approximation for interacting fermion-scalar field models. This method is
applied to an uniform system of relativistic spin-1/2 fermion field coupled,
through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called
quantum scalar plasma model. The renormalization for the resulting Gaussian
mean-field equations, both static and dynamical, are examined and initial
conditions discussed. We also investigate solutions for the gap equation and
show that the energy density has a single minimum.Comment: 21 pages, latex, 4 postscript figures, new sections, some literary
changes, notation corrections, accepted for publication in Phys. Rev
Effective Widths and Effective Number of Phonons of Multiphonon Giant Resonances
We discuss the origin of the difference between the harmonic value of the
width of the multiphonon giant resonances and the smaller observed value.
Analytical expressions are derived for both the effective width and the average
cross-section. The contribution of the Brink-Axel mechanism in resolving the
discrepancy is pointed out.Comment: 9 pages, 4 figure
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