English

Mixing time for the asymmetric simple exclusion process in a random environment

Probability 2024-02-20 v2 Mathematical Physics math.MP

Abstract

We consider the simple exclusion process in the integer segment [1,N] [1, N] with kN/2k\le N/2 particles and spatially inhomogenous jumping rates. A particle at site x[1,N]x\in [ 1, N] jumps to site x1x-1 (if x2x\ge 2) at rate 1ωx1-\omega_x and to site x+1x+1 (if xN1x \le N-1) at rate ωx\omega_x if the target site is not occupied. The sequence ω=(ωx)xZ\omega=(\omega_x)_{ x \in \mathbb{Z}} is chosen by IID sampling from a probability law whose support is bounded away from zero and one (in other words the random environment satisfies the uniform ellipticity condition). We further assume E[logρ1]<0\mathbb{E}[ \log \rho_1 ]<0 where ρ1:=(1ω1)/ω1\rho_1:= (1-\omega_1)/\omega_1, which implies that our particles have a tendency to move to the right. We prove that the mixing time of the exclusion process in this setup grows like a power of NN. More precisely, for the exclusion process with Nβ+o(1)N^{\beta+o(1)} particles where β[0,1)\beta\in [0,1), we have in the large NN asymptotic Nmax(1,1λ,β+12λ)+o(1)tMixN,kNC+o(1) N^{\max\left(1,\frac {1}{\lambda}, \beta+ \frac 1 {2\lambda}\right)+o(1)} \le t_{\mathrm{Mix}}^{N,k} \le N^{C+o(1)} where λ>0\lambda>0 is such that E[ρ1λ]=1\mathbb{E}[\rho_1^{\lambda}]=1 (λ=\lambda=\infty if the equation has no positive root) and CC is a constant which depends on the distribution of ω\omega. We conjecture that our lower bound is sharp up to sub-polynomial correction.

Keywords

Cite

@article{arxiv.2102.02606,
  title  = {Mixing time for the asymmetric simple exclusion process in a random environment},
  author = {Hubert Lacoin and Shangjie Yang},
  journal= {arXiv preprint arXiv:2102.02606},
  year   = {2024}
}

Comments

35 pages, 5 figures

R2 v1 2026-06-23T22:50:10.607Z