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Title: Particle-vibration coupling within covariant density functional theory

Covariant density functional theory, which has so far been applied only within the framework of static and time-dependent mean-field theory, is extended to include particle-vibration coupling (PVC) in a consistent way. Starting from a conventional energy functional, we calculate the low-lying collective vibrations in the relativistic random phase approximation (RRPA) and construct an energy-dependent self-energy for the Dyson equation. The resulting Bethe-Salpeter equation in the particle-hole (p-h) channel is solved in the time blocking approximation (TBA). No additional parameters are used, and double counting is avoided by a proper subtraction method. The same energy functional, i.e., the same set of coupling constants, generates the Dirac-Hartree single-particle spectrum, the static part of the residual p-h interaction, and the particle-phonon coupling vertices. Therefore, a fully consistent description of nuclear excited states is developed. This method is applied for an investigation of damping phenomena in the spherical nuclei with closed shells {sup 208}Pb and {sup 132}Sn. Since the phonon coupling terms enrich the RRPA spectrum with a multitude of p-hxphonon components, a noticeable fragmentation of the giant resonances is found, which is in full agreement with experimental data and with results of the semiphenomenological nonrelativistic approach.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Physik-Department der Technischen Universitaet Muenchen, D-85748 Garching (Germany) and Institute of Physics and Power Engineering, RU-249033 Obninsk (Russian Federation)
  2. (Germany)
  3. (Russian Federation)
Publication Date:
OSTI Identifier:
21003455
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.75.064308; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BETHE-SALPETER EQUATION; COLLECTIVE MODEL; COUPLING; DENSITY FUNCTIONAL METHOD; GIANT RESONANCE; LEAD 208; NUCLEAR FRAGMENTATION; PARTICLES; PHONONS; RANDOM PHASE APPROXIMATION; RELATIVISTIC RANGE; SELF-ENERGY; SHELL MODELS; SPHERICAL CONFIGURATION; TIME DEPENDENCE; TIN 132; VIBRATIONAL STATES