Optimizing phonon space in the phonon-coupling model

Abstract

We present a new scheme to select the most relevant phonons in the phonon-coupling model, named here time-blocking approximation (TBA). The new criterion, based on the phonon-nucleon coupling strengths rather than on $B(EL)$ values, is more selective and thus produces much smaller phonon spaces in TBA. This is beneficial in two respects: first, it curbs down the computational cost, and second, it reduces the danger of double counting in the expansion basis of TBA. We use here TBA in a form where the coupling strength is regularized to keep the given Hartree-Fock ground state stable. The scheme is implemented in an RPA and TBA code based on the Skyrme energy functional. We first explore carefully the cutoff dependence with the new criterion and can work out a natural (optimal) cutoff parameter. Then we use the freshly developed and tested scheme to a survey of giant resonances and low-lying collective states in six doubly magic nuclei looking also on the dependence of the results when varying the Skyrme parametrization.

9 figures, 3 tables

References in corpus (2)

• The Skyrme Interaction in finite nuclei and nuclear matter
• Relativistic RPA plus phonon-coupling analysis of pygmy dipole resonances

Cited by in corpus (6)

• The Compression-Mode Giant Resonances and Nuclear Incompressibility
• Self-consistency in the phonon space of the particle-phonon coupling model
• Low-energy M1 excitations in ${}^{208}$Pb and the spin channel of the Skyrme energy-density functional
• Excitation spectra of exotic nuclei in a self-consistent phonon-coupling model
• Including particle-vibration coupling in the Fayans functional. Odd-even mass differences of semi-magic nuclei
• Multiphonon structure of high-spin states in ${}^{40}$Ca, ${}^{90}$Zr, and ${}^{208}$Pb