Covariant response theory beyond RPA and its application

Abstract

The covariant particle-vibration coupling model within the time blocking approximation is employed to supplement the Relativistic Random Phase Approximation (RRPA) with coupling to collective vibrations. The Bethe-Salpeter equation in the particle-hole channel with an energy dependent residual particle-hole (p-h) interaction is formulated and solved in the shell-model Dirac basis as well as in the momentum space. The same set of the coupling constants generates the Dirac-Hartree single-particle spectrum, the static part of the residual p-h interaction and the particle-phonon coupling amplitudes. This approach is applied to quantitative description of damping phenomenon in even-even spherical nuclei with closed shells ${}^{208}$Pb and ${}^{132}$Sn. Since the phonon coupling enriches the RRPA spectrum with a multitude of ph$\otimes$phonon states a noticeable fragmentation of giant monopole and dipole resonances is obtained in the examined nuclei. The results are compared with experimental data and with results of the non-relativistic approach.

12 pages, 4 figures, Proceedings of the NSRT06 Conference

References in corpus (11)

• A New Parameterization for the Lagrangian Density of Relativistic Mean Field Theory
• Quasiparticle random phase approximation based on the relativistic Hartree-Bogoliubov model
• Superheavy Nuclei in the Relativistic Mean Field Theory
• Covariant theory of particle-vibrational coupling and its effect on the single-particle spectrum
• Dipole states in stable and unstable nuclei
• Quasiparticle time blocking approximation within the framework of generalized Green function formalism
• The time-dependent relativistic mean-field theory and the random phase approximation
• Particle-vibration coupling within covariant density functional theory
• Ground-state properties of deformed proton emitters in the relativistic Hartree-Bogoliubov model
• Description of electric dipole excitations in the tin isotopes within the quasiparticle time blocking approximation
• Addendum to: Solar neutrino oscillation parameters after first KamLAND results