Spectral fluctuations and the statistics of electromagnetic transition intensities and electromagnetic moments in using the framework of the shell model

The fluctuation properties of energy spectrum, electromagnetic transition intensities and electromagnetic moments in nucleus are investigated within the framework of the interacting shell model, using a realistic effective interaction for the N82-model space with a core. The spectral fluctuations (i.e., the nearest-neighbors level spacing distribution and the Δ3 statistic), the distributions of the electromagnetic transition intensities and of the electromagnetic moments are well described by the Gaussian orthogonal ensemble of random matrices. A clear quantum signature of the breaking of chaoticity (i.e., a transition towards regularity) is observed when the single particle energies are increased.