Vacuum Structure in Intense Fields


Book Description

This Advanced Study Institute (ASI) brought together two distinct ·"schools of approach" to Quantum Electrodynamics (QED) in the presence of intense, external, electromagnetic fields, in an effort to lay a joint foundation for a needed theoretical explanation of the sharp e+ e- "resonances" observed in the scattering of very heavy IOns. These (GSI/Darmstadt) experiments, whose history, latest reconfirmations, and most recent data were presented in three opening sessions (Bokemeyer, Koenig), show a smooth background of positron (e+) production, as a function of e+ kinetic energy. Superimposed upon this background are four very sharp peaks, of narrow widths (~ 30 KeV) and of clear experimental significance ('" 5 standard deviations). Most ofthese peaks correspond to sharp, essentially back-to-back electron-positron emission in the ions' center of mass. Following the approach of "supercritical" potential theory (SPT), where the total ionic charge unit Z satisfies Z > 137, it has been possible to provide a detailed and apparently correct understanding of the smooth e+ e- background; a coherent description of different facets of this approach, emphasizing the nature of the charged, supercritical vacuum, was described by the authors responsible for the invention of SPT (Greiner, Muller, Rafelski). In addition, predictions for related phenomena were outlined by other lecturers using the SPT approach (Bawin, Soff, SsJrensen).




Quantum Electrodynamics of Strong Fields


Book Description

The fundamental goal of physics is an understanding of the forces of nature in their simplest and most general terms. Yet there is much more involved than just a basic set of equations which eventually has to be solved when applied to specific problems. We have learned in recent years that the structure of the ground state of field theories (with which we are generally concerned) plays an equally funda mental role as the equations of motion themselves. Heisenberg was probably the first to recognize that the ground state, the vacuum, could acquire certain prop erties (quantum numbers) when he devised a theory of ferromagnetism. Since then, many more such examples are known in solid state physics, e. g. supercon ductivity, superfluidity, in fact all problems concerned with phase transitions of many-body systems, which are often summarized under the name synergetics. Inspired by the experimental observation that also fundamental symmetries, such as parity or chiral symmetry, may be violated in nature, it has become wide ly accepted that the same field theory may be based on different vacua. Practical ly all these different field phases have the status of more or less hypothetical models, not (yet) directly accessible to experiments. There is one magnificent ex ception and this is the change of the ground state (vacuum) of the electron-posi tron field in superstrong electric fields.







Defense Conversion Strategies


Book Description

A North Atlantic Treaty Organization (NATO) Advanced Studies Institute (AS I) on Defense Conversion Strategies was held at the Atholl Palace Hotel, Pitlochry, Perthshire, Scotland, from July 2 through July 14, 1995. This publication is the proceedings of the Institute. The NATO Advanced Studies Institute program of the NATO Science Committee is a unique and valuable forum under whose auspices over one thousand international tutorial meetings have been held since the inception of the program in 1959. The ASI is intended to be primarily a high-level teaching activity at which a carefully defined subject is presented in a systematic and coherently structured program. The subject is treated in considerable depth by lecturers eminent in their fields and of international standing. The subject is presented to other experts or practitioners who will already have specialized in the field or possess an advanced general background appropriate to the topic. The ASI is aimed at an audience at the post-doctoral level. This does not exclude advanced graduate students or other senior participants with qualifications and achievements in the subject of the ASI or rclated areas. This ASI was prompted by several events in the defense environment.







Frontiers Of Accelerator Technology - Proceedings Of The Joint Us-cern-japan International School


Book Description

This volume contains the proceedings of the Topical course on Frontiers of Accelerator Technology, jointly organized by the CERN Accelerator School, the KEK Accelerator School and the US Particle Accelerator School. It was held at Maui, Hawaii, November 3-9, 1994. The purpose was to disseminate knowledge on the latest ideas and developments in the technology of particle accelerators by bringing together world known experts and younger scientists in the field. It was intended for individuals with professional interest in accelerator physics and technology, for graduate students, for post-docs and for those working in accelerator-based sciences.The motivation to conceive and build accelerators comes from a most fundamental need of man — to understand and control the world around us. With beams and their associated accelerators, scientists and engineers can gain understanding of the nature of matter and modify matter not possible by other means. Areas already influenced by the developments in accelerator technology are high energy and nuclear physics, atomic and molecular physics, condensed matter physics and the biological sciences. There is also a growing number of applications in medicine and industry. The program was as follows: lectures in superconductivity, magnets, RF, feedback, instrumentation, high power sources, beam stability and novel accelerator techniques; seminars on accelerator applications, the role of government and industry, and perspectives on future technology; round table: the high energy accelerator frontier; four short courses, each including 8 hours of lectures, problems and tutorials on superconducting magnets, superconducting rf, instrumentation and linacs.This book aims to summarize all the currently available knowledge on the technology driving the development of particle beams for science, medicine, and industry. It is the most up-to-date and unique collection of information on this technology presently available.




Coherence Phenomena in Atoms and Molecules in Laser Fields


Book Description

This volume contains the lectures and communications presented at the NATO Advanced Research Workshop (NATO ARW 900857) which was held May 5-10, 1991 at McMaster University, Hamilton, Ontario, Canada. A scientific commitee made up of P.P. Lambropoulos (USC & Crete), P.8. Corkum (NRC, Ottawa), and H. B. vL. van den Heuvell (FOM, Amsterdam) guided the organizers, A.D. Bandrauk (Sherbrooke) and S.C. Wallace (Toronto) in preparing a programme which would cover the latest advances in the field of atom and molecule laser interactions. Since the last meeting held in July 1987 on "Atomic and Molecular Processes with Short Intense Laser Pulses", NATO ASI vol 1718 (Plenum Press 1988), considerable progress has been made in understanding high intensity effects on atoms and the concomitant coherence effects. After four years, the emphasis is now shifting more to molecules. The present volume represents therefore this trend with four sections covering the main interests of research endeavours in this area: i) Atoms in Intense Laser-Fields ii) Molecules in Intense Laser Fields iii) Atomic Coherences iv) Molecular Coherences The experience developed over the years in multiphoton atomic processes has been very useful and is the main source of our understanding of similar processes in molecules. Thus ATI (above threshold ionization) has been found to occur in molecules as well as a new phenomenon, ATD (above-threshold dissociation). Laser-induced avoided crossings of molecular electronic surfaces is also now entering the current language of high intensity molecular processes.




Modern Nonlinear Optics, Volume 119, Part 2


Book Description

The new edition will provide the sole comprehensive resource available for non-linear optics, including detailed descriptions of the advances over the last decade from world-renowned experts.




High Energy Physics Index


Book Description




Advances in Nuclear Dynamics 2


Book Description

The 12th Winter Workshop on Nuclear Dynamics carried on the tradition, started in 1978, of bringing together scientists working in all regimes of nuclear dynamics. This broad range of related topics allows the researcher attending the Workshop to be exposed to work that normally would be considered outside his/her field, but could po tentially add a new dimension to the understanding of his/her work. At Snowbird, we brought together experimentalists working with heavy ion beams from 10 MeV/nucleon up to 200 GeV /nucleon and theoretical physicists working in diverse areas ranging from antisymmetrized fermionic dynamics to perturbative quantum chromo dynamics. Fu ture work at RHIC was discussed also, with presentations from several of the experimen tal groups. In addition, several talks addressed issues of cross-disciplinary relevance, from the study of water-drop-collisions, to the multi-fragmentation of buckyballs. Clearly the field of nuclear dynamics has a bright future. The understanding of the nuclear equation of state in all of its manifestations is being expanded on all fronts both theoretically and experimentally. Future Workshops on Nuclear Dynamics will certainly have much progress to report. Gary D. Westfall Wolfgang Bauer Michigan State Universzty 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.