As the end of the nineteenth century neared, it was clear to many in the physics community that if only Newton's equations plus Maxwell's equations could be solved adequately, there would really be nothing very new in physics on a fundamental level. Then came relativity and quantum mechanics. As we now approach the end of the twentieth century, it is clear to many in the physics community that if one could adequately solve somebody's gauge field theory (or somebody else's string model), then nothing fundamentally new would ever again enter into physics. To others in the physics community, it is somewhat doubtful that our present physical understanding of the world, especially of quantum mechanics, has reached such a pinnacle.This conference was organized to discuss the present state of affairs in our knowledge, both experimental and theoretical, of the basic tenets of quantum mechanics. Many fields of physics in which quantum mechanics plays a central role were included: (i) atomic and molecular beams; (ii) photon beams; (iii) atomic interference in atom-surface physics and atom wire physics; (iv) Bose-condensed systems; (v) quantum '1/f' noise; (vi) quantum electrodynamics effects in water, colloidal systems and biological systems; (vii) quantum interference in neutrino physics; (viii) periodic-in-time driven quantum systems; (ix) superconducting quantum circuits; and (x) quantum computer circuit elements.The large variety of different topics, all of current importance, allowed for various viewpoints that are usually not present when conferences devoted to narrower topics are held. The cross-fertilization of ideas was greatly appreciated by the participants, and will be of equal interest to the reader of the proceedings.

As the end of the nineteenth century neared, it was clear to many in the physics community that if only Newton's equations plus Maxwell's equations could be solved adequately, there would really be nothing very new in physics on a fundamental level. Then carne relativity and quantum mechanics. As we now approach the end of the twentieth century, it is clear to many in the physics community that if one could adequately solve somebody's gauge field theory (or somebody else's string model), then nothing fundamentally new would ever again enter into physics. To others in the physics community, it is somewhat doubtful that our present physical understanding of the world, especially of quantum mechanics, has reached such a pinnacle. This conference was organized to discuss the present state of affairs in our knowledge, both experimental and theoretical, of the basic tenets of quantum mechanics. Many fields of physics in which quantum mechanics plays a central role were included: (i) atomic and molecular beams; (ii) photon beams; (iii) atomic interference in atom-surface physics and atom wire physics; (iv) Bose-condensed systems; (v) quantum "1/f" noise; (vi) quantum electrodynamics effects in water, colloidal systems and biological systems; (vii) quantum interference in neutrino physics; (viii) periodic-in-time driven quantum systems; (ix) superconducting quantum circuits; and (x) quantum computer circuit elements. The large variety of different topics, all of current importance, allowed for various viewpoints that axe usually not present when conferences devoted to narrower topics are held. The cross-fertilization of ideas was greatly appreciated by the participants, and will be of equalinterest to the reader of the proceedings.

The foundations of quantum mechanics has acquired tremendous importance in recent years for three reasons: First, a large number of experiments have tested concepts which previously were purely theoretical. Second, ideas from the foundations of quantum mechanics are being applied now to many fields such as condensed matter physics, quantum statistics, quantum cosmology and quantum gravity. Third, difficulties in constructing a quantum cosmology and theory of gravity have made many theorists examine the foundations of quantum theory to see if quantum mechanics itself needs to be modified. Very distinguished physicists from around the world gave talks on their recent research on a variety of theoretical and experimental aspects on these subjects at this conference. Contents: The Berry Phase as an Appropriate Correspondence Limit of the Aharonov-Anandan Phase in a Simple Model (J Christian & A Shimony)On the Nature of the Transition in Quantum Field Theory from Flat to Curved Space-Time (P J Camp & J L Safko)The Aharonov-Bohm Effect without Gauge Fields – A Paradox (I Klebanov & L Susskind)Geometrical and Topological (AN)Holonomies in Optical Experiments (R Y Chiao)Some Global Problems in Gauge Theories (F Wilczek)Experimental Verification of the Aharonov-Casher Effect for Neutrons with a Crystal Interferometer (G I Opat et al.)Fundamental Aspects of Quantum Theory Related to the Problem of Quantizing Black Holes (G ' t Hooft)A Suggested New Translation Gauge Invariance for Space-time (D Bohm)Spin and the Aharonov-Bohm Effect (C R Hagen)The Aharonov-Bohm Effect in Small Resistive Devices (R A Webb)Wave Geometry: A Plurality of Singularities (M V Berry)Analogue of the Aharonov-Bohm Effect for Black Holes and Strings (S B Giddings)Closing in on a Renormalizable and Unitary Point-Local Quantum Field Theory of Gravity (Y Ne ' eman & C-Y Lee)Gravitational Chern-Simons Term, Anyons and AB (S Deser)Experimental Confirmation of the Aharonov-Bohm Effect by Electron Holography (A Tonomura)A Geometric View of Quantum Mechanics (J Anandan)Towards a Two Vector Formulation of Quantum Mechanics (Y Aharonov & D Rohrlich)Musings on Quantum Statistics (A Zee)Topology, Quantum Theory and Dynamics (E C G Sudarshan)and other papers Readership: Experimental and theoretical physicists. keywords:

This volume is an outgrowth of the Second International Workshop on Macroscopic Quantum Coherence and Computing held in Napoli, Italy, in June 2000. This workshop gathered a number of experts from the major Universities and Research Institutions of several countries. The choice of the location, which recognizes the role and the traditions of Naples in this field, guaranteed the participants a stimulating atmosphere. The aim of the workshop has been to report on the recent theoretical and experimental results on the macroscopic quantum coherence of macroscopic systems. Particular attention was devoted to Josephson devices. The correlation with other atomic and molecular systems, exhibiting a macroscopic quantum behaviour, was also discussed. The seminars provided both historical overview and recent theoretical ground on the topic, as well as information on new experimental results relative to the quantum computing area. The first workshop on this topic, held in Napoli in 1998, has been ennobled by important reports on observations of Macroscopic Quantum Coherence in mesoscopic systems. The current workshop proposed, among many stimulating results, the first observations of Macroscopic Quantum Coherence between macroscopically distinct fluxoid states in rf SQUIDs, 20 years after the Leggett's proposal to experimentally test the quantum behavior of macroscopic systems. Reports on observations of quantum behaviour in molecular and magnetic systems, small Josephson devices, quantum dots have also been particularly stimulating in view of the realization of several possible q-bits.

The foundations of quantum mechanics has acquired tremendous importance in recent years for three reasons: First, a large number of experiments have tested concepts which previously were purely theoretical. Second, ideas from the foundations of quantum mechanics are being applied now to many fields such as condensed matter physics, quantum statistics, quantum cosmology and quantum gravity. Third, difficulties in constructing a quantum cosmology and theory of gravity have made many theorists examine the foundations of quantum theory to see if quantum mechanics itself needs to be modified. Very distinguished physicists from around the world gave talks on their recent research on a variety of theoretical and experimental aspects on these subjects at this conference

The Seventh Rochester Conference on Coherence and Quantum Optics was held on the campus of the University of Rochester during the four-day period June 7 - 10, 1996. More than 280 scientists from 33 countries participated. This book contains the Proceedings of the meeting. This Conference differed from the previous six in the series in having only a limited number of oral presentations, in order to avoid too many parallel sessions. Another new feature was the introduction of tutorial lectures. Most contributed papers were presented in poster sessions. The Conference was sponsored by the American Physical Society, by the Optical Society of America, by the International Union of Pure and Applied Physics and by the University of Rochester. We wish to express our appreciation to these organizations for their support and we especially extend our thanks to the International Union of Pure and Applied Physics for providing financial assistance to a number of speakers from Third World countries, to enable them to take part in the meeting.