R. F. Casten 

Research Interests

Professor Casten's career has focused on research in nuclear structure, especially the nature of collectivity and and collective modes, the evolution of collectivity with nucleon number, the study of phase/shape transitions in nuclei, the onset of collectivity and deformation, and the p-n interaction. Over three decades, these interests have led to major contributions to the study of the Nilsson model, Coriolis coupling, pairing vibrations, hexadecapole deformations, algebraic models (IBA) and correlations of nuclear observables. In work relating to the IBA, he co-discovered that O(6) symetry (196Pt) and the O(6)->SU(3) transition region, invented the IBA symmetry triangle and (with Warner) developed the Consistent Q Formalism. He carried out the first significant tests of the IBA for a deformed nucleus (168Er) and of the IBFA (109Pd). As a result of these studies 196Pt and 168Er have become the classic testing grounds for nuclear models. His work on the p-n interaction has demonstrated its critical role in shape/phase transitions in heay nuclei. This work led to the invention of the NpNn scheme and other correlation schemes for the evolution of structure that has revealed new and remarkable simplicities in evolutionary trajectories that are challenging both theory and new experiments.

In the last few years, a prime emphasis in his research has been on structural evolution in nuclei (as a function of nucleon number), in particular the concepts of phase transitions in finite systems, phase co-existence, and critical point nuclei. This has led F. Iachello to develop the concept of critical point symmetries, which Prof. Casten and his group are actively studying. This research has led to the discovery of the first empical examples of critical point symmetries in nuclei, to a new mapping of structural evolution in nuclei with nucleon number, and to studies of new classes of geometrical models of atomic nuclei. Further, an extensive recent program has been the study of empirical proton-neutron interactions including the discovery of the first direct correlation between empirical growth rates (with nucleon number) of collectivity and deformation in nuclei and empirical strengths of the p-n interaction. Also, this work provided the first extensive test of Density Functional Theory calculations of p-n interactions over the entire nuclear chart. Prof. Casten has recently been Chair of the Nuclear Science Advisory Committee (NSAC) and will be Chair of the Division of Nuclear Physics (DNP) of the American Physical Society in 2008.

Finally, he has a deep and active interest in the physics opportunities provided by radioactive nuclear beams and has been a leader of the national and international RNB community. Indeed, he has been the Chairman of the ISL steering Committee since its inception and chaired the Writing Panel for the White Paper from the Columbus, Ohio, Workshop.