Lecture series on the emergence and nature of collectivity in nuclei, and its principal driver, the valence p-n interaction (2/5)

There are two overarching approaches to nuclear structure, a microscopic one focusing on nucleon motions and their interactions, and a macroscopic one focusing on the properties of the many-body system as a whole, with its quantum numbers, symmetries, shapes, and shape transitions.  These lectures will focus on both perspectives.  The evolution of structure will be surveyed, with emphasis on regions of rapid structural change, especially in the form of Quantum Phase Transitions, and in the models that can describe the shapes and excitation modes of transitional and collective nuclei.  The emphasis in the latter will be on the IBM which is the most general and parameter-efficient model for low lying quadrupole collectivity in nuclei.  The microscopic perspective will be on the p-n interaction which links the microscopic and macroscopic approaches to nuclear structure.

Part 2: seminar on 'A mini-Wigner effect in heavy nuclei and the 0[110] or ZQT transformation'

Following the discovery of a valence mini-Wigner energy in heavy nuclei [1], it has been recognized that orbits linked by changes in Nilsson quantum numbers of 0[110] have enhanced p-n interactions.  This will be discussed in terms of spatial overlaps of Nilsson orbits, showing the large values for proton and neutron orbits differing solely by the addition of a single quantum in the z-direction (the ZQT or z-quantum transformation).  This approach suggests a new way of understanding the development and locus of collectivity in nuclei, and may give a new way to view the structure of major shells in heavy nuclei
[1]R.B. Cakirli, K. Blaum and R.F. Casten, PRC 82, 061304 (2010)
[2]D. Bonatsos, S. Karampagia, R. B.Cakirli, R. F. Casten, K.Blaum, to be published