Phase Space Representation for Open Quantum Systems within the Lindblad Theory

The Lindblad master equation for an open quantum system with a Hamiltonian containing an arbitrary potential is written as an equation for the Wigner distribution function in the phase space representation. The time derivative of this function is given by a sum of three parts: the classical one, the quantum corrections and the contribution due to the opening of the system. In the particular case of a harmonic oscillator, quantum corrections do not exist.Comment: 19 pages, Latex, accepted for publication in Int. J. Mod. Phys.

On scission configuration in ternary fission

A static scission configuration in cold ternary fission has been considered in the framework of two mean field approaches. The virial theorems has been suggested to investigate correlations in the phase space, starting from a kinetic equation. The inverse mean field method is applied to solve single-particle Schredinger equation, instead of constrained selfconsistent Hartree-Fock equations. It is shown, that it is possible to simulate one-dimensional three-center system via inverse scattering method in the approximation of reflectless single-particle potentialsComment: 11 pages, 1 figure, Fusion Dynamics at the Extremes, Int. Workshop, Dubna, Russia, May 2000. To be published in World Scientifi

Cluster radioactivity of Th isotopes in the mean-field HFB theory

Cluster radioactivity is described as a very mass asymmetric fission process. The reflection symmetry breaking octupole moment has been used in a mean field HFB theory as leading coordinate instead of the quadrupole moment usually used in standard fission calculations. The procedure has been applied to the study of the ``very mass asymmetric fission barrier'' of several even-even Thorium isotopes. The masses of the emitted clusters as well as the corresponding half-lives have been evaluated on those cases where experimental data exist.Comment: Contribution to XIV Nuclear Physics Workshop at Kazimierz Dolny, Poland, Sept. 26-29, 200

Ternary configuration in the framework of inverse mean-field method

A static scission configuration in cold ternary fission has been considered in the framework of mean field approach. The inverse scattering method is applied to solve single-particle Schroedinger equation, instead of constrained selfconsistent Hartree-Fock equations. It is shown, that it is possible to simulate one-dimensional three-center system via inverse scattering method in the approximation of reflectless single-particle potentials.Comment: 8 pages, 1 figure, iopart.cls, to be published in Int.J.Mod.Phys.

Pairing and continuum effects in nuclei close to the drip line

The Hartree-Fock-Bogoliubov (HFB) equations in coordinate representation are solved exactly, i.e., with correct asymptotic boundary conditions for the continuous spectrum. The calculations are preformed with effective Skyrme interactions. The exact HFB solutions are compared with HFB calculations based on box boundary conditions and with resonant continuum Hartree-Fock-BCS (HF-BCS) results. The comparison is done for the neutron-rich Ni isotopes. It is shown that close to the drip line the amount of pairing correlations depends on how the continuum coupling is treated. On the other hand, the resonant continuum HF-BCS results are generally close to those of HFB even in neutron-rich nuclei.Comment: 9 figures, corrected ref.

Pairing and alpha-like quartet condensation in N=Z nuclei

We discuss the treatment of isovector pairing by an alpha-like quartet condensate which conserves exactly the particle number, the spin and the isospin. The results show that the quartet condensate describes accurately the isovector pairing correlations in the ground state of systems with an equal number of protons and neutronsComment: 4 pages, to appear in Journal of Physics: Conference Serie

Physical Origin of Density Dependent Force of the Skyrme Type within the Quark Meson Coupling Model

A density dependent, effective nucleon-nucleon force of the Skyrme type is derived from the quark-meson coupling model -- a self-consistent, relativistic quark level description of nuclear matter. This new formulation requires no assumption that the mean scalar field is small and hence constitutes a significant advance over earlier work. The similarity of the effective interaction to the widely used SkM$^*$ force encourages us to apply it to a wide range of nuclear problems, beginning with the binding energies and charge distributions of doubly magic nuclei. Finding acceptable results in this conventional arena, we apply the same effective interaction, within the Hartree-Fock-Bogoliubov approach, to the properties of nuclei far from stability. The resulting two neutron drip lines and shell quenching are quite satisfactory. Finally, we apply the relativistic formulation to the properties of dense nuclear matter in anticipation of future application to the properties of neutron stars.Comment: 2 references added, some changes in the tex