Consider uniformly elliptic random walk on Z d with independent jump rates across nearest neighbour bonds of the lattice. We show that the infinite volume effective diffusion matrix can be almost surely recovered as the limit of finite volume periodized effective diffusion matrices.
We prove a uniform Poincaré inequality for non–interacting unbounded spin systems with a conservation law, when the single–site potential is a bounded perturbation of a convex function with polynomial growth at infinity. The result is then applied to Ginzburg-Landau processes to show diffusive scaling of the associated spectral gap.
We consider the anisotropic three dimensional XXZ Heisenberg ferromagnet in a cylinder with axis along the 111 direction and boundary conditions that induce ground states describing an interface orthogonal to the cylinder axis. Let L be the linear size of the basis of the cylinder. Because of the breaking of the continuous symmetry around the ^ z axis, the… (More)
Aldous' spectral gap conjecture asserts that on any graph the random walk process and the random transposition (or interchange) process have the same spectral gap. We prove the conjecture using a recursive strategy. The approach is a natural extension of the method already used to prove the validity of the conjecture on trees. The novelty is an idea based… (More)
There is still no universally accepted theory of high-temperature superconductivity. Most models assume that doping creates 'holes' in the valence band of an insulating, antiferromagnetic 'parent' compound, and that antiferromagnetism and high-temperature superconductivity are intimately related. If their respective energies are nearly equal, strong… (More)
We prove new inequalities implying exponential decay of relative entropy functionals for a class of Zero–Range processes on the complete graph. We first consider the case of uniformly increasing rates, where we use a discrete version of the Bakry– Emery criterium to prove spectral gap and entropy dissipation estimates, uniformly over the number of particles… (More)
We consider paths of a one–dimensional simple random walk conditioned to come back to the origin after L steps, L ∈ 2N. In the pinning model each path η has a weight λ N(η) , where λ > 0 and N (η) is the number of zeros in η. When the paths are constrained to be non–negative, the polymer is said to satisfy a hard– wall constraint. Such models are well known… (More)
The paper concerns lattice triangulations, i.e., triangulations of the integer points in a polygon in R<sup>2</sup> whose vertices are also integer points. Lattice triangulations have been studied extensively both as geometric objects in their own right and by virtue of applications in algebraic geometry. Our focus is on random triangulations in which a… (More)
We prove existence of a wetting transition for two types of gradient fields: 1) Continuous SOS models in any dimension and 2) Massless Gaussian model in dimension 2. Combined with a recent result showing the absence of such a transition for Gaussian models above 2 dimensions , this shows in particular that absolute-value and quadratic interactions can… (More)
We consider random walks in a random environment which are generalized versions of well-known effective models for Mott variable-range hopping. We study the homogenized diffusion constant of the random walk in the one-dimensional case. We prove various estimates on the low-temperature behavior which confirm and extend previous work by physicists. 1.… (More)