[en] Abstract only

[en] Abstract only

[en] The Random Phase Approximation (RPA) treatment of nuclear small amplitude vibrations including particle-hole continua is handled in terms of previously developed techniques to treat single-particle resonances in a reaction theoretical framework. A hierachy of interpretable approximation is derived and a simple working approximation is proposed which involves a numerical effort no larger than that involved in standard, discrete RPA calculations. (author)

[en] Indistinguishable quantum particles are called distributed according to quantum Maxwell-Boltzmann statistics if the statistical operator W is Maxwell-Boltzmann symmetric, i.e. if W is a homogeneous product state. It is shown that a state is both Maxwell-Boltzmann and Bose-Einstein symmetric if and only if it is a homogeneous product state of pure states

[en] A procedure is developed to calculate the chemical potential of a system of fermions at low temperatures within the framework of independent particle model. We calculate the energy spectrum of a single particle by equations similar to Bohr-Sommerfeld quantization rule. The behaviour of the chemical potential at various characteristics of the system has been investigated. (author)

[en] We investigate the independent quasiparticle (QP) picture for superdeformed nuclei of the mass-190 region, which is expected to lead to additivity in certain physical quantities. Obvious deviations from additivity are found from both projected shell model calculations and experimental data. The cause of the deviation can be decomposed and identified through this model. Our study suggests that the independent QP picture may not be fully appropriate for this mass region. (author)

No abstract available

[en] If the single particle (sp) potential usub(αν) is the defined in terms of the mass operator Msub(αν)ν) by usub(αν) = Msub(αν)(epsilonν), corresponding to an eigenvector vertical strokeα> of the sp hamiltonian h = t + u, there may exist more than one eigenvalue and besides, the total set of vertical strokeα> may be overcomplete. The consequences of these possibilities, especially their bearings upon the relation between the eigensolutions of h and the nuclear sp (sh) states have been investigated in some detail. The general conclusions obtained are tested by Lipkin's model. It is shown that they are confirmed by this model. (orig.)

No abstract available

[en] Accuracy and stability of single-particle resonance parameters under changes of a ''resonance wave function'' are examined in the context of a projection technique. Implications for their use in nuclear structure calculations are discussed