Aug, 2017
Anderson-Bogoliubov phonons in the inner crust of neutron stars: Dipole excitation in a spherical Wigner-Seitz cell
PHYSICAL REVIEW C
- ,
- Volume
- 96
- Number
- 2
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1103/PhysRevC.96.025806
- Publisher
- AMER PHYSICAL SOC
Background: The Anderson-Bogoliubov (AB) phonon, called also the superfluid phonon, has attracted attentions since it may influence the thermal conductivity and other properties of the inner crust of neutron stars. However, there are a limited number of microscopic studies of the AB phonon where the presence of clusters is explicitly taken into account.
Purpose: We intend to clarify how the presence of clusters affects the AB phonon in order to obtain microscopic information relevant to the coupling between the AB phonon and the lattice phonon.
Methods: The Hartree-Fock-Bogoliubov model and the quasiparticle random-phase approximation formulated in a spherical Wigner-Seitz cell are adopted to describe neutron superfluidity and associated collective excitations. We perform systematic numerical calculations for dipole excitation by varying the neutron chemical potential and the number of protons in a cell.
Results: The model predicts systematic emergence of the dipole AB phonon mode, which, however, exhibits strong suppression of phonon amplitude inside the cluster. We find also that the phonon amplitude around the cluster surface varies with the neutron density. At higher neutron densities (>= 0.006 fm(-3)) the AB phonon mode exhibits behavior similar to the pygmy dipole resonance in neutron-rich nuclei.
Conclusions: The dipole AB phonon mode does not penetrate into the clusters. This suggests that the coupling between the AB phonon and the lattice phonon may be weak.
Purpose: We intend to clarify how the presence of clusters affects the AB phonon in order to obtain microscopic information relevant to the coupling between the AB phonon and the lattice phonon.
Methods: The Hartree-Fock-Bogoliubov model and the quasiparticle random-phase approximation formulated in a spherical Wigner-Seitz cell are adopted to describe neutron superfluidity and associated collective excitations. We perform systematic numerical calculations for dipole excitation by varying the neutron chemical potential and the number of protons in a cell.
Results: The model predicts systematic emergence of the dipole AB phonon mode, which, however, exhibits strong suppression of phonon amplitude inside the cluster. We find also that the phonon amplitude around the cluster surface varies with the neutron density. At higher neutron densities (>= 0.006 fm(-3)) the AB phonon mode exhibits behavior similar to the pygmy dipole resonance in neutron-rich nuclei.
Conclusions: The dipole AB phonon mode does not penetrate into the clusters. This suggests that the coupling between the AB phonon and the lattice phonon may be weak.
- Link information
- ID information
-
- DOI : 10.1103/PhysRevC.96.025806
- ISSN : 2469-9985
- eISSN : 2469-9993
- Web of Science ID : WOS:000408513000006