SU(2) x SU(2) QUASI-SPIN MODEL AND CONSTRAINED HARTREE-FOCK METHOD

In order to study the effectivity for the constrained Hartree-Fock (CHF) method, a quasi-spin model containing two kinds of interaction is proposed. The exact solution of the model Hamiltonian in SU(2)xSU(2) basis, the HF and some CHF solutions as well as the ground state phase transition are discussed.