QUANTUM CHAOS AND ITS APPLICATION

The present article is a note of my lecture in the Aizu University at Oct. 1994. The first part is designed to present an outline of the fie ld called Quantum Chaos for primers. The problems in the quantization of classical system in the presence of chaos, the well-established res ults in this subject and the current status of Quantum Chaos are discu ssed. The second part of this lecture note is devoted to introduce my recent work. Within the framework of the Interacting Boson Model (IBM) , we discuss rotational damping, which has a close relation to tile tr ansition from order to chaos at high spin states. We discuss the basic mechanism of its appearance by showing, tile global properties of the level density and electromagnetic transitions, including their fluctu ation properties in the system governed by the quadrupole-quadrupole i nteraction at highly excited, high spin states. It is demonstrated tha t an unexpected regularity arises due to a quadrupole-quadrupole inter action at high spin state. We present an articulate elucidation on the importance of the higher multipole interactions, which cause the mixi ng among highly excited rotational bands. For the damping width of the rotational bands, an explanation based on the SU(3) limit of the IBM is suggested. This work is done under the collaboration with T. Otsuka and P. von Brentano.