Energy level statistics in particle-rotor model

摘要

Energy level statistics of a system consisting of six particles interacting by delta force in a two-j model coupled with a deformed core is studied in particle-rotor model. For single-j shell (i(13/2)) and two-j shell (g(7/2) + d(5/2)) the exact energies for our statistical analysis are obtained from a full diagonalization of the Hamiltonian, while in two-j case (i(13/2) + g(9/2)) the configuration truncation is used. The nearest-neighbor distribution of energy levels and spectral rigidity are studied as the function of spin. The results of single-j shell are compared with those in two-j case. It is showed that the system becomes more regular when single-j space (i(13/2)) is replaced by two-j shell (g(7/2) + d(5/2)) although the basis size of the configuration space is unchanged. The degree of chaoticity of the system, however, changes slightly when configuration space is enlarged by extending single-j shell (i(13/2)) to two-j shell (i(13/2) + g(9/2)).