Spectral statistics in particles-rotor model and cranking model

Spectral statistics for six particles in single-j and two-j model coupled with a deformed core are studied in the frames of particles-rot or model and cranking shell model. The nearest-neighbor-distribution of energy levels and spectral rigidity are studied as a function of the spin or cranking frequency, respectively. The results of single-j shell are compared with those in two-j case. 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. However, the degree of chaoticity of the system 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). Nuclear chaotic behavior is studied when we take a two-body interaction as delta force and pairing interaction, respectively.