Lattice gas with ``interaction potential''

We present an extension of a simple automaton model to incorporate non-local interactions extending over a spatial range in lattice gases. {}From the viewpoint of Statistical Mechanics, the lattice gas with interaction range may serve as a prototype for non-ideal gas behavior. {}From the density fluctuations correlation function, we obtain a quantity which is identified as a potential of mean force. Equilibrium and transport properties are computed theoretically and by numerical simulations to establish the validity of the model at macroscopic scale.Comment: 12 pages LaTeX, figures available on demand ([email protected]

Entropy and Correlations in Lattice Gas Automata without Detailed Balance

We consider lattice gas automata where the lack of semi-detailed balance results from node occupation redistribution ruled by distant configurations; such models with nonlocal interactions are interesting because they exhibit non-ideal gas properties and can undergo phase transitions. For this class of automata, mean-field theory provides a correct evaluation of properties such as compressibility and viscosity (away from the phase transition), despite the fact that no H-theorem strictly holds. We introduce the notion of locality - necessary to define quantities accessible to measurements - by treating the coupling between nonlocal bits as a perturbation. Then if we define operationally ``local'' states of the automaton - whether the system is in a homogeneous or in an inhomogeneous state - we can compute an estimator of the entropy and measure the local channel occupation correlations. These considerations are applied to a simple model with nonlocal interactions.Comment: 13 pages, LaTeX, 5 PostScript figures, uses psfig. Submitted to Int. J. Mod. Phys.

Mécanique statistique des automates de gaz sur réseau à interactions non-locales

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

The efficiency of some nonparametric competitors to correlogram-based methods

info:eu-repo/semantics/publishe

Levy laws for lattice gas automata

info:eu-repo/semantics/publishe

Effects of microscopic disorder in a simple model for polymerization through heterogeneous catalysis

An important source of controversy concerning the polymerization of olefins through heterogeneous catalysis is the cause of the broad molecular weight distribution (MWD) observed even when the polymer is prepared at constant monomer concentration. In this Letter we show that, apart from the usually invoked chemical and physical mechanisms, additional phenomena related to microscopic disorder could contribute to the MWD broadening. A schematic microscopic model illustrates the argumentation. The extent to which microscopic disorder contributes to the MWD broadening in a real system is discussed. © 1995 The American Physical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe