This anthology is devoted to the theoretical and experimental study of coherent phenomena in quantum optics. Considerable attention is devoted to the investigation of cooperative effects in multilevel molecular and atomic systems. The theoretical analysis is based on a single approach, using the theory of groups, which makes it possible to present the results in a compact and physically elegant form. The results of a detailed experimental and theoretical investigation of the photon echo, self-induced transparency, and nutation are presented. The theory of a coherent resonant mechanism for the interaction of laser radiation with multi atomic molecules which causes "prompt" dissociation is presented. A number of applied pos sibilities, in particular, the control of radiation by laser light and laser isotope separation, are analyzed.

This monograph, "Non-linear Cooperative Effects in Open Quantum Systems: Entanglement and Second Order Coherence" is dedicated to the large auditory of specialists interested in the modern approaches in quantum open systems, cooperative phenomena between excited atoms and the field of the non-linear interaction. Special attention is dedicated to the problems of non-linear interaction with vacuum fields and thermostat with finite temperature, but quantum aspects of laser generation of light in non-linear interaction with finite numbers of cavity modes remain the center of attention. In many situations, the limit to the traditional cooperative phenomena of open quantum systems and thermodynamics are taken into consideration. As the book contains the class of non-linear effects of generations of the particle in such cooperative phenomena, the author's aim was to describe squeezed problems and affect entanglement between the generation photons and phonons in cooperative processes. The new phenomenon of cooperative emission in the single- and two-quantum processes are carefully described for large audiences of specialists in the field of quantum optics and condensed matter physics, chemistry and biology.

The quantum statistical properties of radiation represent an important branch of modern physics with rapidly increasing applications in spectroscopy, quantum generators of radiation, optical communication, etc. They have also an increasing role in fields other than pure physics, such as biophysics, psychophysics, biology, etc. Interesting applications have been developed in high energy elementary particle collisions. The present monograph represents an extension and continuation of the previous monograph by this author entitled Coherence of Light (Van Nostrand Reinhold Company, London 1972, translated into Russian in the Publishing House Mir, Moscow 1974, second edition published by D. Reidel, Dordrecht-Boston 1985) and ofa review chapter in Progress in Optics, Vol. 18 (edited by E. Wolf, North-Holland Publishing Company, Amsterdam 1980) as well. It applies the fundamental tools of the coherent-state technique, as described in Coherence of Light, to particular studies of the quantum statistical properties of radiation interacting with matter. In particular. nonlinear optical processes are considered, and purely quantum phenom ena such as antibunching of photons, their sub-Poisson behaviour and squeezing of vacuum fluctuations are discussed. Compared to the first edition of this book, pub lished in 1984, we have added much more information about squeezing of vacuum fluctuations in nonlinear optical process in this second edition; further we have included the description of experiments and their results performed from that time. Also a new brief chapter on nonlinear dynamics and chaos in quantum statistical optics has been included.

This volume contains a collection of review articles that are extended versions of invited lectures given at the First Pamporovo Winter Workshop on Cooperative Phe nomena in Condensed Matter held in villa "Orlitza" (7th-15th March 1998, Pamporovo Ski Resort, Bulgaria). Selected research works reported at the Workshop have been published in the Journal of Physical Studies - a new International Journal for research papers in experimental and theoretical physics (Lviv University, Lviv, Ukraine). These reviews are supposed to be status reports and present new insights gained from the rapidly developing research of outstanding problems in condensed matter physics such as structural properties and phase transitions in fullerene crystals, super conductivity ofstrongly interacting electrons in copper oxides, spin polarized Fermi liq uids, chaotic vortex filaments in superfluid turbulent Helium-II, desorption induced by electronic transitions in ionic compounds, fluctuation phenomena in superconductors, and quantum critical phenomena in low dimensional magnets and quantum liquids. We have set the material according to the alphabetic order of authors' names although the high temperature superconductivity seems to be the hard kernel in condensed matter physics. The authors have taken care to present the recent advances in their research in a form which is readable and useful not only to experts in the respective field, but also to young scientists. That is why the lectures include a comprehensive introduction to the matter and also an extended discussion of methodical details.