The interacting boson-fermion model has become in recent years the standard model for the description of atomic nuclei with an odd number of protons and/or neutrons. This book describes the mathematical framework on which the interacting boson-fermion model is built and presents applications to a variety of situations encountered in nuclei. The book addresses both the analytical and the numerical aspects of the problem. The analytical aspect requires the introduction of rather complex group theoretic methods, including the use of graded (or super) Lie algebras. The first (and so far only) example of supersymmetry occurring in nature is also discussed. The book is the first comprehensive treatment of the subject and will appeal to both theoretical and experimental physicists. The large number of explicit formulas for level energies, electromagnetic transition rates and intensities of transfer reactions presented in the book provide a simple but detailed way to analyse experimental data. This book can also be used as a textbook for advanced graduate students.

This book gives an account of the properties of the interacting boson model.

These proceedings comprise the contents of a major international conference on Perspectives of the Interacting Boson Model. Occasioned by the 20th Anniversary of this model, and attended by approx. 130 scientists from 29 countries, the topics focused on current and future research, which relates to the IBM. This model has now become one of the standard approaches to nuclear structure and has helped usher in a renaissance in that field and a new, unified perspective that focuses on dynamical symmetries and the key role of the valence nucleons. The algebraic approach fostered by the model is being extended to other fields, including nuclear reactions, molecular physics and baryon structure.

The fundamental model of nuclear structure is the shell model. However, its application has been limited to light nuclei (up to the sd shell) or heavier nuclei with only a few valence nucleons outside closed shells. Its application beyond these limits has been prohibited so far by the largescale of the calculations involved. For the description of nuclei beyond the sd shell having several valence nucleons the introduction of collective models becomes necessary.The first comprehensive phenomenological model of nuclear structure was the geometric collective model of A. Bohr and B.R. Mottelson. An alternative approach was proposed in 1974 by A. Arima and F. Iachello, known as the Interacting Boson Model. This model, which uses group theoretical techniquesin the description of nuclear collective properties, has the advantage of relative simplicity, allowing for detailed calculations of the properties of even medium and heavy nuclei which cannot be reached by the shell model yet. Several extensions and generalizations of the model have appeared overthe last decade. Algebraic descriptions for the effects of clustering, permanent octupole deformation, and giant resonances have also been given. For the description of odd nuclei the Interacting Boson-Fermion Model has been introduced, and nuclear supersymmetries associated with it have beenanalysed.The present text is designed to provide physicists with an accessible introduction to the subject.

Medium heavy nuclei with mass number A=60-90 exhibit a variety of complex collective properties, provide a laboratory for double beta decay studies, and are a region of all heavy N=Z nuclei. This book discusses these three aspects of nuclear structure using Deformed Shell Model and the Spin-Isospin Invariant Interacting Boson Model naturally generated by fermionic SO(8) symmetry. Using these two models, the book describes properties of medium heavy nuclei with mass number A=60-90. It provides a good reference for future nuclear structure experiments using radioactive ion beam (RIB) facilities. Various results obtained by the authors and other research groups are also explained in this book.

This thesis describes a novel and robust way of deriving a Hamiltonian of the interacting boson model based on microscopic nuclear energy density functional theory. Based on the fact that the multi-nucleon induced surface deformation of finite nucleus can be simulated by effective boson degrees of freedom, observables in the intrinsic frame, obtained from self-consistent mean-field method with a microscopic energy density functional, are mapped onto the boson analog. Thereby, the excitation spectra and the transition rates for the relevant collective states having good symmetry quantum numbers are calculated by the subsequent diagonalization of the mapped boson Hamiltonian. Because the density functional approach gives an accurate global description of nuclear bulk properties, the interacting boson model is derived for various situations of nuclear shape phenomena, including those of the exotic nuclei investigated at rare-isotope beam facilities around the world. This work provides, for the first time, crucial pieces of information about how the interacting boson model is justified and derived from nucleon degrees of freedom in a comprehensive manner.