Mesoscopic Nuclear Physics From Nucleus To Quantum Chaos To Quantum Signal Transmission

This book summarizes the recent development of nuclear science as an important part of mesoscopic physics, the intermediate world between the macroscopic and microscopic. This fast developing area with many practical applications includes complex atoms, molecules (including biological), nuclei, small-scale solid state systems, and future quantum computers. The complexity of the problem appears due to the richness of problems, from the necessity to study individual quantum levels, to the fundamental features of statistics and thermodynamics.

The goal of the Workshop was to open the way for exchange of ideas between physicists working in different areas of quantum physics but studying the objects of mesoscopic nature which reveal important generic features and allow for similar approaches. Among these objects are complex nuclei, atoms and molecules, nanoscale condensed matter systems, atomic clusters, atoms in traps, prototypes of quantum computers etc. The Workshop WNMP-2004 was organized with the idea of bringing together researchers actively working on the multitude of mesoscopic problems in various areas and, through cross-fertilizing discussions, make an attempt to bridge the existing gaps, find a common language and clean the way for future collaborations. The topics of common interest included general features of mesoscopic systems; experimental, theoretical and computational methods used for their studies; coherent phenomena, such as superfluidity and superconductivity; many-body quantum chaos; marginally stable and open systems; phase transitions and thermodynamic properties (an exciting subject with contradictory opinions reflected in the Proceedings).

Mesoscopic physics unifies physical systems “in between” microworld and macroworld. Such systems are sufficiently large to reveal certain statistical regularities, but they are sufficiently small to allow physicists to study, both theoretically and experimentally, individual quantum states. The conference covers common and specific features of those systems (nuclei, complex atoms and molecules, atomic traps, sold state micro- and nano-devices, prototypes of future quantum computers). This young field is rapidly developing opening new ideas and technological breakthroughs.

This volume contains the proceedings of the NATO Advanced Research Workshop on `Quantum Chaos -- Theory and Experiment', held at the Niels Bohr Institute, University of Copenhagen, from 28 May to 1 June 1991. The work brings together leading quantum chaos theorists and experimentalists and greatly improves our understanding of the physics of quantum systems whose classical limit is chaotic. Quantum chaos is a subject of considerable current interest in a variety of fields, in particular nuclear physics, chemistry, statistical mechanics, atomic physics, condensed matter physics and nonlinear dynamics. The volume contains lectures about the currently most active fronts of quantum chaos, such as scars, semiclassical methods, quantum diffusion, random matrix spectra, quantum chaos in atomic and nuclear physics, and possible implications of quantum chaos for the problem of quantum measurement. Part of the book -- The Physics of Quantum Measurements -- is dedicated to the memory of John Bell.

Until now the important concept of quantum chaos has remained somewhat ill defined. This volume tackles the ubiquitous borderline between classical andquantum mechanics, studying in particular the semiclassical limit of chaotic systems. The effects of disorder from dynamics and their relation to stochastic systems, quantum coherence effects in mesoscopic systems, and the relevant theoretical approaches are fruitfully combined in this volume. The major paradigms of what is called quantum chaos, random matrix theory and applications to condensed matter and nuclear physics are presented. Detailed discussions of experimental work with particular emphasis on atomic physics are included. The book is highly recommended for graduate-student seminars.

The aim of this book is to present a statistical theory of wave scattering by complex systems -systems which have a chaotic classical dynamics, as in the case of microwave cavities and quantum dots, or possess quenched randomness, as in the case of disordered conductors— with emphasis on mesoscopic fluctuations. The universal character of the statistical behavior of these phenomena is incorporated in a natural way by approaching the problem from a Maximum-Entropy viewpoint -Shannon's information entropy is maximized, subject to the symmetries and constraints that are physically relevant— within the powerful, non-perturbative Theory of Random Matrices. This is a distinctive feature of the present book that greatly motivated our writing it. Another reason is that it collects in one place the material and notions -derived from the published work of the authors in collaboration with several co-workers, as well as from the work of others— which are scattered through research journals and textbooks on the subject. To make the book self-contained, we present in Chapters 2 and 3 the quantum theory of scattering, set in the context of quasi-one-dimensional, multichannel systems, thus related directly to scattering problems in mesoscopic physics. Chapter 4 discusses the linear-response theory of quantum electronic transport, adapted to the context of mesoscopic systems. These chapters, together with Chapter 5 on the Maximum-Entropy Approach and Chapter 8 on weak localization, have been written in a pedagogical style, and can be used as part of a graduate course. Chapters 6 and 7 discuss the problem of electronic transport through classically chaotic cavities and quasi-one-dimensional disordered systems. There are many exercises, most of them worked out in detail, distributed throughout the book. This should help graduate students, their teachers and the research scholars interested generally in the subject of quantum transport through disordered and chaotic systems in their preparation for it, and beyond.