538 research outputs found
Periodic Orbits and Deformed Shell Structure
Relationship between quantum shell structure and classical periodic orbits is
briefly reviewed on the basis of semi-classical trace formula. Using the
spheroidal cavity model, it is shown that three-dimensional periodic orbits,
which are born out of bifurcation of planar orbits at large prolate
deformations, generate the superdeformed shell structure.Comment: 8 pages including 8 figures, Talk at the Conference on Frontiers of
Nuclear Structure, July 29th - August 2nd, 2002, UC Berkele
A simple approach to the chaos-order contributions in nuclear spectra
The simple one-parameter nearest neighbor-spacing distribution (NNSD) is
suggested for statistical analysis of nuclear spectra. This distribution is
derived within the Wigner-Dyson approach in the linear approximation for the
level repulsion density of quantum states. The obtained NNSD gives the
individual information on the Wigner and Poisson contributions in agreement
with that of the statistical experimental distributions of collective states in
deformed nuclei. Using this NNSD, one finds that the symmetry breaking due to
the fixing of projections of the angular momentum of collective states enhances
a chaos as a shift of the NNSD from the Poisson to Wigner distribution
behavior.Comment: 6 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1711.0184
Semiclassical approaches to nuclear dynamics
The extended Gutzwiller trajectory approach is presented for the
semiclassical description of nuclear collective dynamics, in line with the main
topics of the fruitful activity of V.G. Solovjov. Within the Fermi-liquid
droplet model, the leptodermous effective surface approximation was applied to
calculations of energies, sum rules and transition densities for the
neutron-proton asymmetry of the isovector giant-dipole resonance and found to
be in good agreement with the experimental data. By using the Strutinsky shell
correction method, the semiclassical collective transport coefficients such as
nuclear inertia, friction, stiffness, and moments of inertia can be derived
beyond the quantum perturbation approximation of the response function theory
and the cranking model.The averaged particle-number dependence of the low-lying
collective vibrational states are described in good agreement with basic
experimental data, mainly due to an enhancement of the collective inertia as
compared to its irrotational flow value. Shell components of the moment of
inertia are derived in terms of the periodic-orbit free-energy shell
corrections. A good agreement between the semiclassical extended Thomas-Fermi
moments of inertia with shell corrections and the quantum results is obtained
for different nuclear deformations and particle numbers. Shell effects are
shown to be exponentially dampted out with increasing temperature in all the
transport coefficients.Comment: 83 pages, 39 figures, 4 tables, corrected typos and improved Englis
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