Microscopic Basis of the Proton-Neutron Interacting-Boson Model

Abstract

The microscopic basis of the proton-neutron interacting-boson model is studied by comparison with exact shell-model calculations. These calculations show that the 0+ and 2+ collective nucleon pairs, which correspond, respectively, to s and d bosons, play dominant roles in quadrupole collective states. The boson Hamiltonian is constructed microscopically from these pairs, while effects of other pairs are also included by renormalization of the Hamiltonian. Resultant boson spectra agree well with the exact ones.