Investigation of the excitation spectrum of an exact nuclear model by the MCHF approximation

Abstract

Abstract The multiconfiguration Hartree-Fock (MCHF) method is applied to the exactly solvable model of Lipkin, Meshkov and Glick. The energy spectrum is investigated for truncation of the Hartree-Fock basis states in the weak, intermediate and strong coupling regions. There is a good agreement between the computed low lying states and the exact ones, in the weak and intermediate coupling regions. But the low lying spectrum is strongly modified in the strong coupling region. An explanation is given for this behavior. The ground state energy is found to be very well reproduced in all the three regions.