Biomedical subjects

N Boccara

Publications and source records attributed to N Boccara.

8 recordsLinked to original sources

PubMed2001

Convergence to equilibrium in a class of interacting particle systems evolving in discrete time.

We conjecture that for a wide class of interacting particle systems evolving in discrete time, namely, conservative cellular automata with piecewise linear flow diagrams, relaxation to the limit set follows the same power law at critical points. We further describe the structure of the limit sets of such systems as unions of shifts of finite type. Relaxation to the equilibrium resembles ballistic annihilation, with "defects" propagating in opposite directions annihilating upon collision.

Journal Article↗

PubMed2001

Nature of phase transitions in a probabilistic cellular automaton with two absorbing states.

We present a probabilistic cellular automaton with two absorbing states, which can be considered a natural extension of the Domany-Kinzel model. Despite its simplicity, it shows a very rich phase diagram, with two second-order and one first-order transition lines that meet at a bicritical point. We study the phase transitions and the critical behavior of the model using mean field approximations, direct numerical simulations and field theory. The second-order critical curves and the kink critical dynamics are found to be in the directed percolation and parity conservation universality classes, respectively. The first-order phase transition is put in evidence by examining the hysteresis cycle. We also study the "chaotic" phase, in which two replicas evolving with the same noise diverge, using mean field and numerical techniques. Finally, we show how the shape of the potential of the field-theoretic formulation of the problem can be obtained by direct numerical simulations.

Journal Article↗

PubMed1994