The 1982 Antwerp Advanced Study Institute on "Physics of Polarons and Excitons in Polar Semiconductors and Ionic Crystals" took place from July 26 till August 5 at the Conference Center Priorij Corsen donk, a restored monastery, close to the city of Antwerp. It was the seventh Institute in our series which started in 1971. This Advanced Study Institute, which was held fifty years after Landau introduced the polaron concept, can be considered as the third major international symposium devoted to the physics of pola rons. The first such symposium took place in St. Andrews in 1962 under the title "Polarons and Excitons" [I]. The early theoretical developments related to polarons were reviewed in depth at this meeting; the derivation of the polaron hamiltonian by Frohlich, the Frohlich weak coupling theory (and the equivalent weak coupling canonical transformations), the Landau-Pekar and Bogolubov strong coupling theory and the Feynman polaron model formulated with his path integrals. The main emphasis was on the polaron self-energy, effective mass and mobility. From the experimental side the first evidence for polaron effects was provided by the pioneering cyclotron and mobility measurements o~ the silver halides by F. e. Brown and his group. Also the significance of polaron effects for the under standing of excitons in ionic crystals was a central topic in St. Andrews. The second Advanced Study Institute concerning polaron physics was organized at the University of Antwerp (R. U. C. A.

Modern Problems in Condensed Matter Sciences, Volume 27.1: Landau Level Spectroscopy focuses on the processes, reactions, methodologies, and approaches involved in condensed matter sciences, including semiconductors, resonances, and spectroscopy. The selection first tackles cyclotron resonance and phonon-assisted cyclotron resonance. Discussions focus on absorption coefficient for phonon-assisted transitions, effect of a direct current electric field, cyclotron resonance as a kinetics experiment, and cyclotron resonance in the quantum limit. The manuscript then takes a look at polaron effects in cyclotron resonance and electric-dipole spin resonances. The book examines spin-flip Raman scattering and magnetoplasma effects in IV-VI compounds. Topics include magnetoplasma effects in strained semiconductor layers; magnetoplasma effects in two-dimensional systems; experimental and theoretical results of nonmagnetic semiconductors; and experimental and theoretical results of diluted magnetic semiconductors. The manuscript then surveys the interband magneto-optics of semiconductors as diamagnetic exciton spectroscopy and interband magneto-optics in narrow-gap semiconductors. The selection is a dependable source of information for scientists and readers interested in the Landau level spectroscopy.

The book is devoted to the study of the correlation effects in many-particle systems. It presents the advanced methods of quantum statistical mechanics (equilibrium and nonequilibrium), and shows their effectiveness and operational ability in applications to problems of quantum solid-state theory, quantum theory of magnetism and the kinetic theory. The book includes description of the fundamental concepts and techniques of analysis following the approach of N N Bogoliubov's school, including recent developments. It provides an overview that introduces the main notions of quantum many-particle physics with the emphasis on concepts and models. This book combines the features of textbook and research monograph. For many topics the aim is to start from the beginning and to guide the reader to the threshold of advanced researches. Many chapters include also additional information and discuss many complex research areas which are not often discussed in other places. The book is useful for established researchers to organize and present the advanced material disseminated in the literature. The book contains also an extensive bibliography. The book serves undergraduate, graduate and postgraduate students, as well as researchers who have had prior experience with the subject matter at a more elementary level or have used other many-particle techniques.

The book presents the development of the polaron theory and its applications in various fields of physics. Nowadays, methods of the polaron theory are widely used in such sciences as solid state and nuclear physics, chemistry, etc. The monograph includes selected articles, based on the talks, given at the Workshops held in Pushchino in 1993 and 1994. These articles cover different aspects of polaron physics and quantum field theory ranging from nuclear physics to solid state physics and chemistry, they involve both the fundamental research such as bipolarons and the polaron applications to study the self-trapped electron state in various liquids. We hope our book will be of interest to a broad range of readers, which can be able to sense the excitement of the articles.