The XV International Workshop on Condensed Matter Theories was held at the beautiful seaside resort of Mar del Plata, Argentina, during the first week of July, 1991. The first meeting of this workshop took place at the Instituto de Ffsica Teorica, Sao Paulo, Brazil, in 1977, as the first Panamerican Workshop on Condensed Matter Theories. Its purpose was to bring together scientists from the Western countries, to work on many different topics related to the manifold aspects of condensed matter theories. The Workshop was so successful in facilitating exchanges of ideas and techniques pertaining to different areas of scientific endeavour that it quickly transformed itself into a broadly based, interdisciplinary forum for the informal discussion of the interrelation and mutual connections that naturally arise between the diverse disciplines encompassed under the common name condensed matter theories. From the green-house effect to neural networks, all theoretical efforts are interwined in a very complex fashion. The next five workshops were held at Trieste, Italy (1978); Buenos Aires, Argentina (1979); Caracas, Venezuela (1980); Mexico City, Mexico (1981); and St. Louis, Missouri (1982). At the last meeting, in view of the truly international dimension reached by these gatherings, it was decided to substitute the word "International" for "Panamerican", and hold the next meeting, appropriately enough, in Europe.

Klappentext

Proceedings of an international workshop held in Mar del Plata, Argentina, July 1-6, 1991.

Zusammenfassung
Proceedings of an international workshop held in Mar del Plata, Argentina, July 1-6, 1991.

Inhalt
I. Formal Methods.- Requantization in the Time-Dependent Hartree-Fock Method.- A Reaction Theory and the Relation Between Widths and Energy Shifts.- The Control of Chaos.- Berry Phase and its Unitarily Invariant Generalization.- Natanzon Potentials and Spectrum Generating Algebras.- Ground States of Finite Systems and Information Theory.- Information Theory and Quantum Wave Functions.- Decomposition of Signals and Information Theory.- Finite Temperature Correlated Mean Field Treatments and Information Theory.- Dynamics of Quantum Inhibited Processes Through Repeated Measurements.- II. Classical and Quantum Fluids.- Features of HNC/0 Solutions for Symmetric Films of Liquid 4He at T = 0 K.- Compressible Rayleigh-Benard Convection in a Hard Disks System.- Positron Annihilation as a Probe of Localized States in Fluids.- III. Electronic Systems, Atoms Amd Molecules.- Lower Bound Aspects of Fermion Density Functionals.- Solution of the Ornstein-Zernike Equation for a Mixture of Sticky Hard Spheres and Yukawa Closure.- Dynamical Properties of Strongly Coupled Coulomb Systems.- Z-Dependent Perturbation Theory and Complex Rotation Method in Autoionizing States of Atoms.- Selfconsistent Semiclassical Mean Field.- A Simple Approach to Surface States in Covalent Crystals.- Scattering of Atomic Beams in Semiquantum Gases.- Attempts to Calculate the Structure and Dynamics of Macromolecules.- The N-Representability Problem and the Local-Scaling Version of Density Functional Theory.- Atomic and Ionic Information Entropies.- IV. High-Tc Superconductivity.- Superconductivity in Ba1-x Kx Bi O3 Cubic Oxides.- Non. Conventional Superconductivity in BaPb1-xBixO3 and Ba1-xKxBiO3.- The Essential Singularity in BCS Superconductivity Theory and the Gap-to-Tc Ratio.- Search of Superconductivity in Metal Clusters.- The Role of Spin Occupancy in the Electron Gas Problem.- Local Pair Model for the Analysis of Tunneling and Photoemission Experiments in High Tc Superconductors: Superconducting Phase.- Grand-Canonical Description of the Hubbard Hamiltonian.- V. Stochastic Processes.- Reactant Segregation: The Effect of Strong Space Disorder in Diffusion-Limited Bimolecular Reactions.- Interaction Effects in the Toda Soliton Statistics.- Effects of Nonlinear Surface Diffusion on the Scaling of Rough Surfaces.- VI. Nuclear and Particle Physics.- A Direct Approach to the Tamm-Dancoff Approximation.- Finite Size Effects in the Deconfinement Transition.- The Hyperspherical Harmonic Method Applied to 12C and 16O in the ?-Particle Model.- Atomic Small Clusters and Their Correspondence to Nuclear Physics.- VII. Overwiew Talk.- Some Considerations on the Greenhouse Effect and Related Problems.- Contributors.