THE NUMBER SELF-CONSISTENT RENORMALIZED RANDOM PHASE APPROXIMATION

I. Unna

Mohsen Jemaï

Within the 1D Hubbard model, linear closed chains with various numbers of sites are considered in particle–particle self-consistent random phase approximation (SCRPA) for the T-matrix. Encouraging results with a minimal numerical effort are obtained, confirming earlier results with this theory for other models. SCRPA solves the two-site problem exactly. It therefore contains the two electrons and high density Fermi gas limits correctly.

Tatiana N. Antsygina, V. A. Slyusarev, А. В. Свидзинский

А. V. Avdeenkov, Daniel S. Kosov, A.I. Vdovin

A method taking account of a deviation of state occupation numbers from the thermal RPA prescriptions is elaborated to study collective excitations in hot nuclei. This thermal renormalized random phase approximation (TRRPA) is from Ken-Ji Hara and D.J. Rowe. In developing the TRRPA, a formalism of the thermofield dynamics (TFD) is used. Some numerical results are given for the SU(2) model.

Daniel R. Rohr, Maria Hellgren, Eberhard K. U. Gross

Jiali Liao

A quasi-spin model containing two kinds of interactions is proposed. Tbe exact solutionsof the model Hamiltonian on SU(2)×SU(2) basis, the ground-state phase transition and theK-structure of the wave functions are discussed. The effectivity of HF approximation isalso studied in this model.