Fundamental Aspects of Quantum Theory

Thi's book collects the contributions to the NATO Advanced Research WJrkshop on "FundaIrental Aspects of Quantum 'Iheory", held at the Centro di Cultura Scientifica "Alessandro Volta", Villa Olma, Carro, Italy, 2-7 September 1985. The rreeting was dedicated to the rremory of the late pro fessor Piero Caldirola, a prominent member of the Physics Departrrent of the University of r1ilan and a native of Como. The aim of the workshop has been to present several recent experi rrental results and theoretical developrrents concerning the various fa cets of quantum physics. The breadth of scope of the rreeting was in accordance with Professor Caldirola's vast scientific interests, and fostered communication among experirrental physicists, theoretical and mathematical physicists, and nEthematicians, working in different but related fields. Indeed, lectu rers endeavoured to make their contributions understandable to people acquainted with the problem but not necessarily familiar with the tech nical details; and these efforts were successful, as indicated by the frequent private discussions which took place among participants belon ging to different breeds and brands. 1ne rreeting was made up of six one-day sessions, each of them addres sing to a specific aspect of quantum theory: 1. General Problems and Crucial Experinents; with emphasis on sin gle-particle interference eh~rirrents of neutrons and of photons, and on the rreasurerrent problem. 2. Quantization and Stochastic Processes; including stochastic quan tization of gauge fields, stochastic description of supersyrnmetric fields, quantum stochastic calculus and stochastic mechanics.

Inhalt
General Problems and Crucial Experiments.- Are Coherent States the Natural Language of Quantum Theory?.- The Classical Behaviour of Measuring Instruments.- A Continuous Superselection Rule as a Model of Classical Measuring Apparatus in Quantum Mechanics.- Quantum Interference Effect for Two Atoms Radiating a Single Photon.- Neutron Interferometry and Quantum Mechanics.- An Attempt at a Unified Description of Microscopic and Macroscopic Systems.- On the Quantum Theory of Continuous Measurements.- Conditional Expectations on Jordan Algebras.- Quantization and Stochastic Processes.- Stochastic Quantization of Gauge Fields and Constrained Systems.- Brownian Motion, Markov Cosurfaces, Higgs Fields.- Stochastic Description of Supersymmetric Fields with Values in a Manifold.- Quantum Stochastic Calculus in Fock space: A Review.- Quantum Markov Processes Driven by Bose Noise.- Stochastic Interpretation of Emission and Absorption of the Quantum of Action.- Probabilistic Expression for the Solution of the Dirac Equation in Fourier Space.- Are Dirac Electrons Faster than Light?.- Sojourn Times and First Hitting Times in Stochastic Mechanics.- Chaotic Behaviour in Quantum Mechanics.- Quantum Systems Periodically Perturbed in Time.- Chaotic Ionization of Highly-Excited Hydrogen Atoms by a Microwave Electric Field.- Possible Evidence of Deterministic Chaos for the Sinusoidally-Driven Weakly-Bound Electron.- Quantization of Non-Integrable Systems: the Hydrogen Atom in a Magnetic Field.- Quantum Ergodicity and Chaos.- Microscopic and Macroscopic Levels of Description New Techniques and Results.- Some Fundamental Properties of the Ground State of Atoms and Molecules.- Mass/Energy Gap Associated to Symmetry Breaking: A Generalized Goldstone Theorem for Long Range Interactions.- Embeddingas a Description of the Relation Between Macro- and Microphysics.- Some Applications of Semigroups.- N-Level Systems Interacting with Bosons: Semiclassical Limits.- Bose-Einstein Condensation in Some Interacting Systems.- General Aspects of Gauge Theories.- Charge, Anomalies and Index Theory.- Adiabatic Phase Shifts for Neutrons and Photons.- The Gauge Principle in Modern Physics.- Infinite Dimensional Lie Algebras and Quantum Physics.- The Spins of Cyons and Dyons.- Beyond the Hall Effect: Pratical Engineering from Relativistic Quantum Field Theory.- Generalized Aharonov-Bohm Experiments with Neutrons.- Round-Table Discussion on the Aharonov-Bohm Effect.- The Aharonov-Bohm Effect is Real Physics not Ideal Physics.- Again About an Old Stuff: The Aharonov-Bohm Effect.- Against the Existence of the Aharonov-Bohm Effect.- Theories Without AB Effect Misrepresent the Dynamics of the Electromagnetic Field.- Some Cases of the Aharonov-Bohm Effect: Electron Scattering on Magnetic Strings.- Global Gauge Invariance in Two-Dimensional Quantum Mechanics.- Gravity in Quantum Mechanics.- Stability of Matter.- Ihe Gravitational Phase Transition.- Gravitational and Rotational Effects on Superconductors.- Quantum Fields on Manifolds: an Interplay Between Quantum Theory, Statistical Thermodynamics and General Relativity.- Quantum Field Theory in Gravitational Background.- Classical Scattering Theory on the Schwarzschild Metric and the Construction of Quantum Linear Fields on Black Holes.- The Stochastic versus the Euclidean Approach to Quantum Fields on a Static Space-Time.- Quantum Theory in Vector Bundles.- Anomalies and Their Cancellation.- Remarks about Metric Tensors on Fractal Structures.- Short Communications.- A New Gauge Without Any Ghost for Yang-Mills Theory.- UnitaryFormalism for Time-Dependent Problems.- Finite Temperature Quantum Electrical Network Theory.- Two Remarks on the Physical Content of Stochastic Mechanics.- The LambShift for Resonances: Complex Dilations and Coupling Constant Thresholds in Relativistic Quantum Mechanics.- Energy Density and Roughening in the 3-D Ising Ferromagnet.- Bose-Einstein Condensation of Free Photons.- Variational Principle in Quantum Mechanics.- Geometric Quantum Mechanics.- Spectral Sum Rules for Confinement Potentials.- Metrology of Space-Time Dimension.- Chronological Disordering and the Absence of Correlations between Infinitely Separated States.- On Solutions of Quantum Stochastic Integral Equations.