New Results on Quantum Chaos in Atomic Nuclei

In atomic nuclei, ordered and chaotic states generally coexist. In this paper the transition from ordered to chaotic states will be discussed in the framework of roto-vibrational and shell models. In particular for $^{160}Gd$, in the roto-vibrational model, the Poincar\`e sections clearly show the transition from order to chaos for different values of rotational frequency. Furthermore, the spectral statistics of low-lying states of several $fp$ shell nuclei are studied with realistic shell-model calculations.