This book has evolved from lectures devoted to applications of the Wentzel - Kramers – Brillouin- (WKB or quasi-classical) approximation and of the method of 1/N −expansion for solving various problems in atomic and nuclear physics. The intent of this book is to help students and investigators in this field to extend their knowledge of these important calculation methods in quantum mechanics. Much material is contained herein that is not to be found elsewhere. WKB approximation, while constituting a fundamental area in atomic physics, has not been the focus of many books. A novel method has been adopted for the presentation of the subject matter, the material is presented as a succession of problems, followed by a detailed way of solving them. The methods introduced are then used to calculate Rydberg states in atomic systems and to evaluate potential barriers and quasistationary states. Finally, adiabatic transition and ionization of quantum systems are covered.

This expanded and updated well-established textbook contains an advanced presentationof quantum mechanics adapted to the requirements of modern atomic physics. Itincludes topics of current interest such as semiclassical theory, chaos, atom optics andBose-Einstein condensation in atomic gases. In order to facilitate the consolidationof the material covered, various problems are included, together with completesolutions. The emphasis on theory enables the reader to appreciate the fundamentalassumptions underlying standard theoretical constructs and to embark on independentresearch projects. The fourth edition of Theoretical Atomic Physics contains anupdated treatment of the sections involving scattering theory and near-thresholdphenomena manifest in the behaviour of cold atoms (and molecules). Special attentionis given to the quantization of weakly bound states just below the continuum thresholdand to low-energy scattering and quantum reflection just above. Particular emphasisis laid on the fundamental differences between long-ranged Coulombic potentialsand shorter-ranged potentials falling off faster than 1/r2 at large distances r. The newsections on tunable near-threshold Feshbach resonances and on scattering in two spatialdimensions also address problems relevant for current and future research in the fieldof cold (and ultra-cold) atoms. Graduate students and researchers will find this book avaluable resource and comprehensive reference alike.

This new edition presents the recent developments in atomic physics. Beginning with a review of quantum mechanics, the book covers important areas of theoretical atomic physics, including semiclassical theory, periodic orbit theory, scaling properties for atoms in external fields, threshold behavior of ionization cross sections, and classical quantum dynamics of two-electron atoms.

In this revised and expanded edition, in addition to a comprehensible introduction to the theoretical foundations of quantum tunneling based on different methods of formulating and solving tunneling problems, different semiclassical approximations for multidimensional systems are presented. Particular attention is given to the tunneling of composite systems, with examples taken from molecular tunneling and also from nuclear reactions. The interesting and puzzling features of tunneling times are given extensive coverage, and the possibility of measurement of these times with quantum clocks are critically examined.In addition, by considering the analogy between evanescent waves in waveguides and in quantum tunneling, the times related to electromagnetic wave propagation have been used to explain certain aspects of quantum tunneling times. These topics are treated in both non-relativistic as well as relativistic regimes. Finally, a large number of examples of tunneling in atomic, molecular, condensed matter and nuclear physics are presented and solved.

Master's Thesis from the year 2011 in the subject Physics - Quantum Physics, Shahjalal University of Science and Technology (Department of Physics), course: Nanostructure Physics, language: English, abstract: This book contains a comprehensive account of application of WKB method to pure Physics of nanostructures containing single or symmetric double barrier V(x) in their band model in presence of longitudinal magnetic field applied along x direction. It concentrates on effects on transmission coefficient of single and symmetric double barriers by three dimensional electron gas (3DEG). Analytical expressions for longitudinal magnetic field dependent transmission coefficient of single and symmetric double barrier of general shape are obtained first. These general expressions are then used to obtain analytical expressions of longitudinal magnetic field dependent transmission coefficient of single and symmetric double barriers of many different shapes we encounter in studying nanostructure Physics. This is followed by thorough numerical investigation to bring out effects of longitudinal magnetic field on transmission coefficient of all these barriers. Comparisons with standard results where available showed excellent agreements. Results of numerical investigation have been explained completely. The book makes well documented, with thorough calculation and discussion, pure Physics of semiconductor nanostructures.

"Quantum Mechanics describes the phenomena that matter and light exhibit on an atomic scale and so the study of atomic physics, nuclear physics and solid state physics are impossible without a clear understanding of the basic concepts and formalism of Quantum Mechanics. Since Physics deals essentially with numbers - the measurement of physical quantities and the calculations of these quantities on the basis of a theoretical framework - adequate attention has been paid to computation and numerical exercises. This book aims to promote a comprehensive understanding of the subject with illustrative examples."--BOOK JACKET.