In both the present volume of Advances in Nuclear Physics and in the next volume, which will follow in a few months' time, we have stretched our normal pattern of reviews by including articles of more major proportions than any we have published before. As a result we have only three review articles in Volume 5. From the beginning of this series it has been our aim, as editors, to achieve variation in the scope, style, and length of individual articles sufficient to match the needs of the individual topic, rather than to restrain authors within rigid limits. It has not been our experience that this flexibility has led to unnecessary exuberance on the part of the authors. We feel that the major articles now entering the series are entirely justified. The article by Professor Delves on "Variational Techniques in the Nuclear Three-Body Problem" is an authoritative, definitive article on a subject which forms a cornerstone of nuclear physics. If we start with two body interactions, then the three-nucleon system is, perhaps, the only many nucleon system whose exact description may lie within the scope of human ingenuity. In recent years some new techniques of scattering theory, origi nating mostly in particle physics, have led to a great deal of new interest in the nuclear three-body problem. In this series we have had two articles (by Mitra and by Duck) on the new approaches."

This book of proceedings collects the papers presented at the workshop on "Diagnostics for Experimental Fusion Reactors" held at Villa Monastero, Varenna (Italy) September 4-12, 1997. This workshop was the seventh organized by the International School of Plasma Physics "Piero Caldirola" on the topic of plasma diagnostics and the second devoted to the diagnostic studies for the International Thermonuclear Experimental Reactor (ITER). The proceedings of the first workshop on ITER diagnostics were published by Plenum Press in 1996 with the title "Diagnostics for Experimental Thermonuclear Fusion Reactors". While many of the ideas and studies reported in the first workshop remain valid, there has been sub stantial progress in the design and specification of many diagnostics for ITER. This moti vated a second workshop on this topic and the publication of a new book of proceedings. ITER is a joint venture between Europe, Japan, Russia and USA in the field of con trolled thermonuclear fusion research. The present aim of ITER is to design an experimental fusion reactor that can demonstrate ignition and sustained burn in a magnetically confined plasma. To achieve this goal, a wide range of plasma parameters will have to be measured reliably. It is also anticipated that diagnostics will be used much more extensively as input to control systems on ITER than on present fusion devices and this will require increased relia bility and long-term stability.

I am most pleased and, in a way, I feel honored to write the Foreword for the book The Hanle Effect and Level-Crossing Spectroscopy, which covers such a very wide range of applications not only in the initial areas of atomic and molecular physics, but also in solid state physics, solar physics, laser physics, and gravitational metrology. To link these fields together in a coherent way has been the merit of the editors of the book, who attracted most distinguished authors for writing the chapters. In retrospect to Hanle's discovery of quantum mechanical coherence between two quantum states about 65 years ago, this book demonstrates the enormous impact and central importance the effect has had, and most vividly still has, on modern physics. On the other hand, the concept of quantum mechanical coherence, which is an outgrowth of the linear super position principle of quantum states, has been evident through a consider able number of experimental methods beyond the original Hanle effect; some of these methods were only recently discovered or applied and they have indeed revolutionized research fields such as atomic collision physics."

An (e,2e) experiment is the measurement of an electron impact ionization process where both the exiting electrons are detected in coincidence. Such measurements are almost at the limit of what can be known, in quantum mechanical terms, and its description presents a substantial theoretical challenge. There are at least two very good reasons for studying (e,2e) and related processes. In the first place we are now only beginning to understand the dynamics of the collision process. The range and sophistication of present experiments allow us to identify kinematic regimes where delicate and subtle effects can be observed, stretching current theories to their limit. Secondly, the multiple coincident technique offers us the possibility of an analytical tool that could be used to probe the structure of the target, be it atom, molecule, thin film or surface. Measurements are now being performed at threshold on H, on the inner shell levels of Au and Ag using projectiles at relativistic energies, with spin-polarized electrons on Li, on a myriad of molecules in symmetric, noncoplanar kinematics, and on He in a multitude of different geometries. The technique has recently been extended to excitation ionization (e,3e) and (gamma,2e) experiments. Major theoretical advances have also been made, but much still remains to be done. This volume contains the invited papers that were presented at the Workshop on (e,2e) and related processes which took place in September/October 1992 in Cambridge, UK. The three major review papers which it contains together form an excellent introduction to this new and rapidly expanding area of physics and set the scene for the wide range of research contributions, both experimental and theoretical, from the leading scientists in the field.

The present work represents a unique undertaking in scientific publishing to honor Nick Metropolis, who passed away in October, 1999. Nick was the last survivor of the Manhattan Project that began during World War II in Los Alamos and later became the Los Alamos National Laboratory. In this volume, some of the leading scientists and humanists of our time have contributed essays related to their respective disciplines exploring various aspects of future developments in science, technology, and society. Speculations on the future developments of science and society, philosophy, national security, nuclear power, pure and applied mathematics, physics and biology, particle physics, computing, information science, among many others, are included. Contributors include: H. Agnew * R. Ashenhurst * K. Baclawski * G. Baker * N. Balazs * J.A. Freed * R. Hamming * M. Hawrylycz * O. Judd * D. Kleitman * M. Krieger * N. Krikorian * P. Lax * J.D. Louck * T. Puck * M. Raju * R. Richtmyer * J. Schwartz * R. Sokolowski * E. Teller * M. Waterman

The theoretical chemist is accustomed to judging the success of a theoretical prediction according to how well it agrees with an experimental measurement. Since the object of theory is the prediction of the results of experiment, that would appear to be an entirely satisfactory state ofaffairs. However, ifit is true that "the underlying physicallaws ...for the whole ofchemistryare ...completely known" (1), thenit shouldbepossible,atleastinprinciple, topredict theresults of experiment moreaccurately than they canbe measured. Ifthe theoreticalchemist could obtain exact solutions ofthe Schrodinger equation for many-body systems, then the experimental chemist would soon become accustomed to judging the success ofan experimental measurement by how well it agrees with a theoretical prediction. In fact, it is now possible to obtainexact solutions ofthe Schrodinger equation for systems ofa few electrons(2-8). These systems include the molecular ion Ht, the molecule H , the reaction intermediate H-H-H, the unstable pair H-He, the 2 stable dimer He2' and the trimer He3. The quantum Monte Carlo method used in solving the time-independent Schrodinger equation for these systems is exact in that it requires no physical or mathematical assumptions beyond those of the Schrodinger equation. As in most Monte Carlo methods there is a statistical or sampling error which is readily estimated.

The NATO . Advanced Research Insti tute on Nonequilibrium Processes in Partially Ionized Gases was held at Acquafredda di Maratea during 4-17 June 1989. The Institute considered the interconnections between scattering and transport theories and modeling of nonequilibrium systems generated by electrical discharges, emphasizing the importance of microscopic processes in affecting the bulk properties of plasmas. The book tries to reproduce these lines. In particular several contributions describe scattering cross sections involving electrons interacting with atoms and molecules in both ground and excited states (from theoretical and experimental point of view), of energy transfer processes as well as reactive ones involving excited molecules colliding with atoms and molecules as well as with metallic surfaces. Other contributions deal with the basis of transport theories (Boltzmann and Monte Carlo methods) for describing the bulk properties of non equilibrium plasmas as well as with the modeling of complicated systems emphasizing in particular the strong coupling between the Boltzmann equation and excited state kinetics. Finally the book contains several contributions describing applications in different fields such as Excimer Lasers, Negative Ion Production, RF Discharges, Plasma Chemistry, Atmospheric Processes and Physics of Lamps. The Organizing Committee gratefully acknowledges the generous financial support provided by the NATO Science Committee as well as by Azienda Autonoma di Soggiorno e Turismo of Maratea, by University of Bari, by C. N. R. (Centro di Studio per la Chimica dei Plasmi and Comitato per la Chimica), by ENEA, by Lawrence Livermore Laboratory and by US Army Research Office.

This understandable and inspiring book brings together both theorists and experimentalists working on the properties of nuclear and hadronic matter produced in heavy-ion collisions in various energy ranges. The main focus is on experimental signals revealing the possible phase changes of the matter.

In this new textbook on physical chemistry, fundamentals are introduced simply yet in more depth than is common. Topics are arranged in a progressive pattern, with simpler theory early and more complicated theory later. General principles are induced from key experimental results. Some mathematical background is supplied where it would be helpful. Each chapter includes worked-out examples and numerous references. Extensive problems, review, and discussion questions are included for each chapter. More detail than is common is devoted to the nature of work and heat and how they differ. Introductory Caratheodory theory and the standard integrating factor for dGrev are carefully developed. The fundamental role played by uncertainty and symmetry in quantum mechanics is emphasized. In chemical kinetics, various methods for determined rate laws are presented. The key mechanisms are detailed. Considerable statistical mechanics and reaction rate theory are then surveyed. Professor Duffey has given us a most readable, easily followed text in physical chemistry.

Since the third Workshop on "Laser Interaction and Related Plasma Phenomena" in 1973, one area within the scope of this con ference received increased attention: laser fusion. This possi bility was emphasized in February 1977 in a Seminar on US energy policies at The Hartford Graduate Center by John F. O'Leary, Head of the Federal Energy Administration, who said that "by the year 2100, *** laser fusion will be coming along, giving us a new age of choice". Efforts in research and development were stepped up to investigate new concepts of laser ignition of controlled nuclear reactions. Here, one expects no radioactive waste from fuel. Th~ deuterium-tritium reaction - the only one which may be possible with magnetic field confinement in tokamaks - has a highly radio active tritium cycle, while, in principle, laser reactions are possible with pure deuterium, hydrogen-boron or others. The worldwide progress in laser compression was not only stim ulated by the energy crisis, but also by its advancements. In our first Workshop in 1969 F. Floux of the French Limeil Laboratories described his experiments, which led, only one month later, to the production of fusion neutrons in such large numbers as had not been achieved up to then (see appendix of Vol. I these Proceedings).

Californium-252 is a neutron emitter with a high specific activity, making it useful in a variety of applications, the most spectacular of which is in brachytherapy for cancer patients. Radiation oncology has exhausted nearly every option for treating radioresistant tumors by photon brachytherapy, and therefore new types of radiation need to be studied to improve the curability of cancer. Audience: Californium brachytherapy is used in only a few radiation therapy centers in the world, so the book will be highly instructive for radiation oncologists, medical physicists and radiobiologists. The nuclear techniques used in clinical applications may also interest nuclear physicists and engineers.

The International Symposium on Supercomputing - New Horizon of Computational Science was held on September 1-3, 1997 at the Science MuseuminTokyo, tocelebrate60-yearbirthdayofProfessorDaiichiroSug imoto, who hasbeenleadingtheoreticalandnumericalastrophysicsfor 30 years. The conference coveredexceptionally wide range ofsubjects, to follow Sugimoto'saccomplishmentsinmanyfields.Onthefirstdaywehadthree talksonstellarevolutionandsixtalksonstellardynamics. Onthesecond day, six talks on special-purpose computingand four talks on large-scale computing in MolecularDynamicswere given. Onthethirdandthelast day, threetalks on dedicatedcomputerson LatticeQCDcalculationsand sixtalksonpresentandfutureofgeneral-purposeHPCsystemsweregiven. Inaddition, some30posterswerepresentedonvarioussubjectsincompu tationalscience. Instellarevolution, D.Arnett (Univ. ofArizona) gaveanexcellenttalk on the recent development in three-dimensionalsimulation ofSupernova, inparticularonquantitativecomparisonbetweendifferenttechniquessuch asgrid-basedmethodsandSPH (SmoothedParticleHydrodynamics). Y. Kondo (NASA) discussedresentadvanceinthemodelingoftheevolution ofbinarystars, and1.Hachisu(Univ. ofTokyo)discussedRayleigh-Taylor instabilitiesinsupernovae(contributionnotincluded). Instellardynamics, P.Hut(lAS)gaveasuperbreviewonthelong-term evolution ofstellarsystem, J. Makino (Univ. ofTokyo) described briefly theresultsobtainedonGRAPE-4special-purposecomputerandthefollow up project, GRAPE-6, whichisapprovedas ofJune 1997. GRAPE-6will be completed by year 2001 with the peak speed around 200 Tflops. R. Spurzem (Rechen-Inst.) and D. Heggie (Univ. of Edinburgh) talked on recentadvanceinthestudyofstarclusters, andE.Athanassoula(Marseille Observatory) describedthe work doneusingtheirGRAPE-3 systems. S. Ida (TokyoInst. ofTechnology) describedthe result ofthe simulationof theformationofMoon. Thefirst talkoftheseconddaywas given by F-H. Hsu oftheIBMT.J. Watson Research center, on "Deep Blue," the special-purpose computer for Chess, which, forthefirst timeinthehistory, wonthematchwiththe besthumanplayer, Mr. GaryKasparov(unfortunately, Hsu'scontribution isnot included in this volume). Then A. Bakker of Delft Inst. of Tech nology looked back his 20 years ofdevelopingspecial-purpose computers formoleculardynamicsandsimulationofspinsystems. J.Arnoldgavean overviewoftheemergingnewfieldofreconfigurablecomputing, whichfalls inbetweentraditionalgeneral-purposecomputersandspecial-purposecom puters. S.Okumura(NAO)describedthehistoryofultra-high-performance digital signalprocessors for radio astronomy. They havebuilt a machine with 20GaPS performance in early 80s, and keep improvingthe speed. M. Taiji (ISM) told on general aspects of GRAPE-type systems, and T. Narumi (Univ. of Tokyo) the 100-Tflops GRAPE-type machine for MD calculations, whichwillbefinished by 199

Solitons are a well-known and intriguing aspect of nonlinear behavior in a continuous system such as a fluid: a wave propagates through the medium without distortion. Liquid crystals are highly ordered systems without a rigid, long-range structure. Solitons in liquid crystals (sometimes referred to as "walls") have a wide variety of remarkable properties that are becoming important for practical applications such as electroluminescent display. This book, the first review of the subject to be published, contains not only surveys of the existing literature, but presents new results as well.

The 1990 Cargese Summer Institute on ZO-Physics was organized by the Univer- site Pierre et Marie Curie, Paris (M. Levy and J.-L. Basdevant), CERN (M. Jacob), the Universite Catholique de Louvain (D. Speiser and J. Weyers), and the Katholieke Universiteit te Leuven (R. Gastmans), which, since 1975, have joined their efforts and worked in common. It was the ninth Summer Institute on High Energy Physics orga- nized jointly at Cargese by these three universities. Because of the start-up of LEP in the summer of 1989, we broke with our tradition of having our Summer Institutes in the odd years. Indeed, it seemed to us that the many new data from LEP had to be presented in detail as soon as possible in order to prepare the young researchers in particle physics better for the experimental results with which they will be confronted in the coming years. The main theme of the school was therefore ZO-physics, with particular emphasis on the way the experiments at LEP are analyzed. We had one lecturer from each LEP experiment: they agreed among each other to present different topics in e+e- physics. Nevertheless, they made sure that all the major topics were discussed and that the results could be critically compared.

Cosmic electrodynamics is the specific branch of plasma physics which studies electromagnetic phenomena -- mostly the role of electromagnetic forces in dynamics of highly-conducting compressible medium in the solar interior and atmosphere, solar wind, in the Earth's magnetosphere and magnetospheres of other planets as well as pulsars and other astrophysical objects. This textbook is written to be used at several different levels. It is aimed primarily at beginning graduate students who are assumed to have a knowledge of basic physics. Starting from the language of plasma physics, from Maxwell's equations, the author guides the reader into the more specialized concepts of cosmic electrodynamics. The main attention in the book is paid to physics rather than maths. However, the clear mathematical image of physical processes in space plasma is presented and spelled out in the surrounding text. There is not another way to work in modern astrophysics at the quantitative level. The book will also be useful for professional astronomers and for specialists, who investigate cosmic plasmas from space, as well as for everybody who is interested in modern astrophysics.

These are the proceedings of the 141h Winter \Vorkshop on Nuclear Dynamics, the latest of a serif'S of workshops that was started in 1~)78. This series has grown into a tradition. bringing together experimental and theoretical expertise from all areas of the study of nudear dynamics. Following tllf' tradition of the Workshop the program covered a broad range of topics aerof'S a large energy range. At the low energy end llluitifragmentation and its relationship to the nuclear liquid to gas phase transition was disclIssf'd in grf'at df'- tail. New pxpf'rimental data, refined analysis techniques, and new theoretical effort have lead to considerable progress. In the AGS energy range we see the emergence of systematic data that contribute to our understanding of the reaction dynamics. The workshop also showf'd that at CERN energies Itadronic data become much more precise and complet.e and a renewed emphasis on basic hadronic processes and hadronic struc- ture as a precondition to understand the initial conditions and a basis for systematic comparisons. Wolfgang Bauer Michigan State Univcr'sity Hans-Georg Ritter Lawrence Berkeley National Laboratory v PREVIOUS WORKSHOPS The following table contains a list of the dates and locations of the previous Winter Workshops on Nuclear Dynamics as well as the members of the organizing committees. The chairpersons of the conferences are underlined.

The first presentation of the novel interdisciplinary optical remote sensing technique for various ionized diluted media, based on the collisional polarization of the spectoral emission. The book provides a methodology of the impact spectropolarimetic sensing of many solutions to many practical diagnostic problems.

This book contains a broad spectrum of plasma physics areas, from magnetic confinement (tokamaks) to spectroscopy in plasmas. The invited papers of the LAWPP present mini-courses for graduate students and review papers in each area, also updating the new ideas in the field.

This book gives a complete account of electron momentum spectroscopy to date. It describes in detail the construction of spectrometers and the acquisition and reduction of cross-section data, explaining the quantum theory of the reaction and giving experimental verification.

"If there would be no God ~ then what a staff-captain am I?" ~ said one of the characters in a novel by Dostoevskii. In a similar way we can exclaim: "If there would be no nonlinearity ~ than what physics would that be'?". Really, the most interesting and exciting effects are described by non linear equations, and vanish in the linear approximation. For example, the general theory of relativity by A.Einstein comes to mind first - one of the most beautiful physical theories, which is in fact essentially nonlinear. Next, the phase transitions crystal ~ liquid and liquid ~ gas are due to the anhar monicity of inter-particle interactions, to dissociation and infinite motion. Similarly, transitions into the superconducting state or the superftuid would be impossible with purely harmonic interaction potentials. Another bril liant achievement in nonlinear physics was the construction of a laser and the subsequent development of nonlinear optics. The latter describes the in teraction of the matter with light of super-high intensity, when multi-quanta intra-molecular transitions become essential. Last, we should note here the very beautiful mathematical theory ~ the theory of catastrophes. Its subject is the study of invariant general properties of multi-dimensional surfaces in the vicinity of bifurcation points with respect to continuous transformations.

The Twenty-third Coral Gables conference on Unified Symmetry in the Small and in the Large was convened February 2-5, 1995. The shift of the traditional conference time from the last part of January was caused by the 1995 Superbowl's choice of our preferred date for their game. The conference was dedicated to reminiscences of Julian Schwinger. The death of Eugene P. Wigner in the early part of January 1995 was observed with a deep sorrow during the conference. At about that time the news of Asim Barut's death made 1995 an inauspicious year for physicists. In the meantime physics at the frontiers marched on as it did before. There were no path-breaking discoveries, but hope and persistence were still there. In 1964 (the first Coral Gables conference) if we had asked a physicist to give us a sincere opinion on what is "hot" in physics we would have expected him or her to point out the narrow area of their own research. The answer to this question in 1995 is still the same as it would have been in 1964. The mind set is a human quality and even in physics the physicist can respond like a religious believer.

For 75 years the stopping of energetic ions in matter has been a subject of great theoretical and experimental interest. The theoretical treatment of the stopping of ions in matter is largely due to the work of Bohr, 1-3 Bethe,4-6 Bloch,7. s and Lindhard,9-12 and it has been reviewed by Bohr,3 Fano,13 17 20 Jackson,14 Sigmund,15 Ahlen,16 and Ziegler et al. - Soon after the discovery of energetic particle emission from radioactive materials, there was interest in how these corpuscles were slowed down in traversing matter. In 1900, Marie Curie stated 21 the hypothesis that Hies rayons alpha sont des projectiles materiels susceptibles de perdre de leur vitesse en travers ant la matiere. " Early attempts to evaluate this were incon- clusive for there was not yet an accurate proposed model of the atom. Enough experimental evidence was collected in the next decade to make stopping power theory one of the central concerns of those attempting to develop an atomic model. J. J. Thomson, director of the prestigious Cavendish Laboratory, and Niels Bohr, a fresh postdoctoral scientist at Rutherford's Manchester Laboratory, both published almost simultaneously22. 23 an analysis of the stopping of charged particles by matter, and each contained many of their divergent ideas on the model of an atom. Thomson ignored in his paper the Rutherford alpha-particle scattering 24 experiment of a year before. But the nuclear atom with a heavy positively 25 charged core was the basis of Bohr's ideas.

From January 8-13,1990, distinguished physicists from many nations came to Chile to share with each other and with Latin American students exciting recent developments. The occasion was the third of a series of meetings on Quantum Mechanics of Fundamental Systems which are held every two years at the Centro de Estudios Cientificos de Santiago. This volume grew out from that gathering. The meeting was possible thanks to the generous support of the Tinker Foundation, the John D. and Catherine T. MacArthur Foundation, the International Centre for Theoretical Physics, the Ministere des AfIaires Etrangeres et Service Culturel et de Cooperation Scientifique et Technique de France, the Third World Academy of Sciences, and FONDECYT-Chile. The happy winds blowing over Chile at the time enhanced the joy provided by the beauty of the physics discussed. Claudio Teitelboim Jorge Zanelli Santiago, Chile vii Contents Chapter 1 Fractional Statistics in Quantum Mechanics Daniel P. Arovas 1. Introduction...1 2. Charge-Flux Composites...4 3. Dilute Anyon Gases ...6 4. Fractional Statistics in the Quantized Hall Effect ...8 5. Many-Body Theory of the Anyon Gas...16 6. Chern-Simons Field Theory and Fractional Statistics ...20 Appendix: Many Anyons in a Magnetic Field...23 . .