arXiv subjects

J-M Drouffe

Publications and source records attributed to J-M Drouffe.

3 recordsLinked to original sources

arXiv1998

Stationary definition of persistence for finite temperature phase ordering

For the two dimensional kinetic Ising model at finite temperature, the local mean magnetisation $M_t=t^{-1}\int_{0}^tσ(t')\d t'$, simply related to the fraction of time spent by a given spin in the positive direction, has a limiting distribution, singular at $\pm m_0(T)$, the Onsager spontaneous magnetization. The exponent of this singularity defines the persistence exponent $θ$. We also study first passage exponents associated to persistent large deviations of $M_t$, and their temperature dependence.

cond-mat.stat-mech↗

arXiv1998

Coarsening and persistence in a class of stochastic processes interpolating between the Ising and voter models

We study the dynamics of a class of two dimensional stochastic processes, depending on two parameters, which may be interpreted as two different temperatures, respectively associated to interfacial and to bulk noise. Special lines in the plane of parameters correspond to the Ising model, voter model and majority vote model. The dynamics of this class of models may be described formally in terms of reaction diffusion processes for a set of coalescing, annihilating, and branching random walkers. We use the freedom allowed by the space of parameters to measure, by numerical simulations, the persistence probability of a generic model in the low temperature phase, where the system coarsens. This probability is found to decay at large times as a power law with a seemingly constant exponent $θ\approx 0.22$. We also discuss the connection between persistence and the nature of the interfaces between domains.

cond-mat.stat-mech↗

arXiv1997

A simple stochastic model for the dynamics of condensation

We consider the dynamics of a model introduced recently by Bialas, Burda and Johnston. At equilibrium the model exhibits a transition between a fluid and a condensed phase. For long evolution times the dynamics of condensation possesses a scaling regime that we study by analytical and numerical means. We determine the scaling form of the occupation number probabilities. The behaviour of the two-time correlations of the energy demonstrates that aging takes place in the condensed phase, while it does not in the fluid phase.

cond-mat↗