Finite volume approximation of the effective diffusion matrix : the case of independent bond disorder
Finite-size scaling in percolation.
Fires on trees
We consider random dynamics on the edges of a uniform Cayley tree with vertices, in which edges are either flammable, fireproof, or burnt. Every flammable edge is replaced by a fireproof edge at unit rate, while fires start at smaller rate on each flammable edge, then propagate through the neighboring flammable edges and are only stopped at fireproof edges. A vertex is called fireproof when all its adjacent edges are fireproof. We show that as , the terminal density of fireproof vertices converges...
First hitting time and place, monopoles and multipoles for pseudo-processes driven by the equation .
First occurrence time of a large density fluctuation for a system of independent random walks
First-passage competition with different speeds: positive density for both species is impossible.
First-passage percolation on width-two stretches with exponential link weights.
Fluctuation limit theorems for age-dependent critical binary branching systems
We consider an age-dependent branching particle system in ℝd, where the particles are subject to α-stable migration (0 < α ≤ 2), critical binary branching, and general (non-arithmetic) lifetimes distribution. The population starts off from a Poisson random field in ℝd with Lebesgue intensity. We prove functional central limit theorems and strong laws of large numbers under two rescalings: high particle density, and a space-time rescaling...
Fluctuations des temps d'occupation d'un site dans l'exclusion simple symétrique
Fluctuations in a p-spin interaction model
Fluctuations of a surface submitted to a random average process.
Fluctuations of the front in a stochastic combustion model
Fragmentation-Coagulation Models of Phytoplankton
We present two new models of the dynamics of phytoplankton aggregates. The first one is an individual-based model. Passing to infinity with the number of individuals, we obtain an Eulerian model. This model describes the evolution of the density of the spatial-mass distribution of aggregates. We show the existence and uniqueness of solutions of the evolution equation.
Free boundary problem from stochastic lattice gas model
From a kinetic equation to a diffusion under an anomalous scaling
A linear Boltzmann equation is interpreted as the forward equation for the probability density of a Markov process on , where is the two-dimensional torus. Here is an autonomous reversible jump process, with waiting times between two jumps with finite expectation value but infinite variance. is an additive functional of , defined as , where for small . We prove that the rescaled process converges in distribution to a two-dimensional Brownian motion. As a consequence, the appropriately...
Functional inequalities and uniqueness of the Gibbs measure — from log-Sobolev to Poincaré
In a statistical mechanics model with unbounded spins, we prove uniqueness of the Gibbs measure under various assumptions on finite volume functional inequalities. We follow Royer's approach (Royer, 1999) and obtain uniqueness by showing convergence properties of a Glauber-Langevin dynamics. The result was known when the measures on the box [-n,n]d (with free boundary conditions) satisfied the same logarithmic Sobolev inequality. We generalize this in two directions: either the constants may be...
Functional inequalities for discrete gradients and application to the geometric distribution
We present several functional inequalities for finite difference gradients, such as a Cheeger inequality, Poincaré and (modified) logarithmic Sobolev inequalities, associated deviation estimates, and an exponential integrability property. In the particular case of the geometric distribution on we use an integration by parts formula to compute the optimal isoperimetric and Poincaré constants, and to obtain an improvement of our general logarithmic Sobolev inequality. By a...
Functional inequalities for discrete gradients and application to the geometric distribution
We present several functional inequalities for finite difference gradients, such as a Cheeger inequality, Poincaré and (modified) logarithmic Sobolev inequalities, associated deviation estimates, and an exponential integrability property. In the particular case of the geometric distribution on we use an integration by parts formula to compute the optimal isoperimetric and Poincaré constants, and to obtain an improvement of our general logarithmic Sobolev inequality. By a limiting procedure we...
Functional integral representations for self-avoiding walk.