Statistical fluctuations of electromagnetic transition intensities and electromagnetic moments in pf-shell nuclei -: art. no. 064311

We study the fluctuation properties of DeltaT=0 electromagnetic transition intensities and electromagnetic moments in Asimilar to60 nuclei within the framework of the interacting shell model, using a realistic effective interaction for pf-shell nuclei with a Ni-56 core. The distributions of the transition intensities and of the electromagnetic moments are well described by the Gaussian orthogonal ensemble of random matrices. In particular, the transition intensity distributions follow a Porter-Thomas distribution. When diagonal matrix elements (i.e., moments) are included in the analysis of transition intensities, the distributions remain Porter-Thomas except for the isoscalar M1. This deviation is explained in terms of the structure of the isoscalar M1 operator.