4th Granada Seminar on Computational
Physics

Granada, September 9-14, 1996



IV Granada Lectures in Computational Physics
Proceedings published as:

Fourth Granada Lectures in Computational Physics
P.L. Garrido & J. Marro editors
Lecture Notes in Physics, vol. 493, Springer, Berlin 1997

ISBN 3-540-63086-4

This book is out of print.


4th Granada Seminar on
Computational Physics

9-14 September 1996, Granada, Spain

S. Albeverio (Bochum,
Germany)
:
Introduction to the mathematical theory of neural
networks

P. Cordero (Santiago, Chile):
Microscopic
computer simulations of fluids

G. Grinstein (Yorktown
Heights, New York)
:
The statistical mechanics of absorbing states
B. A. Huberman (Palo Alto,
California)
:
The power of cooperation
K. Lindenberg (San Diego,
California)
:
Variational approach to the problem of
exciton-phonon coupling

J. S�nchez-Dehesa (Granada,
Spain)
:
Boltzmann-Shannon entropies of many-particle systems
H. Wio (Bariloche,
Argentina)
:
Nonequilibrium potential in reaction-diffusion
systems

+ contibutions from other participants


Organised by Institute Carlos
I
for Theoretical and Computational Physics of the University of Granada


Abstracts of invited lectures:

AN INTRODUCTION TO THE
MATHEMATICAL THEORY OF NEURAL NETWORKS

Prof. Dr. Sergio
Albeverio

Fakult�t und Institut
f�r Mathematik, Rhur-Universit�t Bochum

We intend to give an introduction
to some mathematical results concerning spin systems of classical statistical mechanics
and neural networks. In particular, we shall discuss equilibrium and dynamical properties
of the Hopfield model. Application to pattern recognition, data compression and speech
recognition will also be mentioned topics.

MICROSCOPIC COMPUTER SIMULATIONS OF
FLUIDS

Prof. Dr. Patricio
Cordero

Departamento de
F�sica, Universidad de Chile, Santiago

The hydrodynamic and kinetic
behavior of a system of N particles is studied by means of Molecular Dynamic techniques
and theoretically. Some of the specific topics will be convective regimes, transport
phenomena, nonlinear constitutive equations and reallistic microscopic boundary
conditions. Efficient algorithms, including real time animations, to simulate such
systemms will be seen as well.

THE STATISTICAL MECHANIS OF
ABSORBING STATES

Prof. Dr. Geoffrey
Grinstein

IBM Watson Research
Center, Yorktown Heights, New York

A large and diverse set of
problems, among them catalysis and other chemical reactions, and the spread of forest
fires and epidemics, are characterized by the presence of one or more absorbing states
-states in which the system becomes trapped indefinitely and in which all nontrivial
activity comes to a halt. In these lectures, we discuss the collective behavior of
different systems with absorbing states. Topics include directed percolation,
multiplicative noise, and systems with infinite numbers of absorbing states.

THE POWER OF COOPERATION
Prof. Dr. Bernardo A.
Huberman

Xerox Research Center,
Palo Alto, California

These lectures will first present a
theory of the performance enhancement that results from cooperating agents working on a
problem and its dynamical consequences for the group as a whole. Second, the results of a
number of computer experiments dealing with the solution of hard constraint satisfaction
problems that support these findings will be shown, and the performance will be compared
with that of non-cooperative algorithms. Third it will be discussed the construction of
cooperative programs for solving hard problems in distributed control using market
mechanisms and the resulting efficiency that it is achieved.

VARIATIONAL APPROACH TO THE PROBLEM
OF EXCITON-PHONON COUPLING

Prof. Dr. Katja
Lindenberg

Department of Chemistry
and Biochemistry, University of California, San Diego

The understanding of the nature and
dynamics of excitations in molecular aggregates continues to pose a challenging problem.
In many molecular systems, excitons are strongly and nonlinearly coupled to lattice
vibrations and other deformations of the medium. The Hamiltonian for these systems can in
general not be diagonalized exactly. We discuss the ground states obtained via
multi-variable variational calculations, analyzing assumptions of incremental
sophistication. These approaches simultaneously incorporate correlations associated with
small and with large polarons, and lead to a unified phase diagram for the system. We
discuss the exciton-phonon configurations implicit in the diagram, and are able to provide
some clarifications to the long-standing question of the existence of a self-trapping
transition.


BOLTZMANN-SHANNON ENTROPIES OF
MANY-PARTICLE SYSTEMS

Prof. Dr. Jes�s
S�nchez-Dehesa

Instituto Carlos I de
F�sica Te�rica y Computacional, Granada

The spatial delocalization of
particles in complex systems as well as its momentum uncertainty is measured by the
Boltzmann-Shannon entropies in position and momentum spaces, respectively. These
quantities, as well as other density functionals which describe fundamental and/or
experimental measurable physical and chemical properties, will be considered by means of
inequality-based techniques together with novel asymptotic methods. Various applications
to finite multielectronic systems will be done.

NONEQUILIBRIUM POTENTIAL IN
REACTION-DIFFUSION SYSTEMS: SOME EXAMPLES

Prof. Dr. Horacio Wio
Centro At�mico
Bariloche E Instituto Balseiro, Bariloche

Notions of stochastic processes and
stability in dynamical systems. Reaction-diffusion systems: pattern formation and
propagation. Turing instability. Examples: pulse propagation in cardiac tissue, neural
signals, spiral structures, chemical reactions, ecological competence, and coexistence in
nonhomogeneous systems. Ballast resistor: electrothermal instability, patterns. Global
stability: nonequilibrium potential. Activator-inhibitor models. Fast inhibition. Long
range inhibition. Spikes, broad strata, oscillating patterns. Some
exercises.


4th Granada Seminar on
Computational Physics

Seminario especializado
sobre aplicaciones cient�ficas del ordenador

Fecha y lugar: del 9 al 14 (incl.) de
septiembre 1996, en la Facultad de Ciencias de la Universidad de Granada

Formato: El programa ser�
desarrollado (generalmente en castellano) por profesores invitados biling�es. Las
sesiones te�ricas ser�n complementadas con pr�cticas. Podr�n presentarse, en
castellano o ingl�s, comunicaciones orales y p�ster. Est� previsto editar las actas,
incluyendo las lecciones invitadas juntamente con una selecci�n de contribuciones de los
asistentes; las actas de ediciones anteriores han aparecido en II Granada Lectures in
Computational Physics
, World Scientific 1993 (ISBN 981-02-1163-5), y en Third
Granada Lectures in Computational Physics
, Lecture Notes in Physics, Springer 1995
(ISBN 3-540-59178-8).

Comit� cient�fico: Julio
F. Fern�ndez (Zaragoza); Pedro L. Garrido (Granada), coordinador cient�fico; Hans J.
Herrmann (J�lich), Rafael de la Llave (Texas, Austin); Joaqu�n Marro (Granada), director
del Seminario.

Inscripci�n:
La cuota de inscripci�n, que incluye libro de actas, es 32.500 Pts para inscripciones
formalizadas antes de 31 de julio 1996, y 40.000 Pts despu�s de esta fecha. Enviar copia
de la hoja de inscripci�n junto con tal�n bancario a nombre de “Seminario de
F�sica Computacional”, o copia del resguardo de transferencia, indicando nombre del
remitente y la observaci�n “Seminario F�sica Computacional (J.Marro)”.

Alojamiento:
Se ofrecen plazas en Colegio Mayor por unas 26.000 Pts (pensi�n completa, domingo a
s�bado, incl.; el precio final ser� determinado pr�ximamente, pues depende del n�mero
de reservas) para quienes transfieran esta cantidad junto con la inscripci�n antes del 30
de junio. Se informa de otros alojamiento a los interesados.

Informaci�n:
Joaqu�n Marro, Instituto Carlos I, Facultad de Ciencias, Universidad de Granada,
E-18071-Granada. Telefax: 958-242 862, -243 385. E-Mail: CPhys @ Goliat.UGR
.ES


COMPUTATIONAL
PHYSICS

IV SEMINARIO en GRANADA sobre F�SICA
COMPUTACIONAL

Facultad de Ciencias,
Universidad de Granada

Granada, 9 a 14 (incl.) de septiembre 1996

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INSCRIPCI�N Y REMITIR LO ANTES POSIBLE, CON TAL�N BANCARIO O COPIA DEL RESGUARDO DE LA
TRANSFERENCIA, A LA ATENCION DE Joaqu�n Marro, Instituto Carlos I, Facultad de Ciencias,
Universidad de Granada, 18071-GRANADA, Espa�a, FAX: 958 – 242 862