English

Percolation of sites not removed by a random walker in $d$ dimensions

Statistical Mechanics 2019-08-22 v2

Abstract

How does removal of sites by a random walk lead to blockage of percolation? To study this problem of correlated site percolation, we consider a random walk (RW) of N=uLdN=uL^d steps on a dd-dimensional hypercubic lattice of size LdL^d (with periodic boundaries). We systematically explore dependence of the probability Πd(L,u)\Pi_d(L,u) of percolation (existence of a spanning cluster) of sites not removed by the RW on LL and uu. The concentration of unvisited sites decays exponentially with increasing uu, while the visited sites are highly correlated -- their correlations decaying with the distance rr as 1/rd21/r^{d-2} (in d>2d>2). Upon increasing LL, the percolation probability Πd(L,u)\Pi_d(L,u) approaches a step function, jumping from 1 to 0 when uu crosses a percolation threshold ucu_c that is close to 3 for all 3d63\le d\le6. Within numerical accuracy, the correlation length associated with percolation diverges with exponents consistent with ν=2/(d2)\nu=2/(d-2). There is no percolation threshold at the lower critical dimension of d=2d=2, with the percolation probability approaching a smooth function Π2(,u)>0\Pi_2(\infty,u)>0.

Keywords

Cite

@article{arxiv.1907.00018,
  title  = {Percolation of sites not removed by a random walker in $d$ dimensions},
  author = {Yacov Kantor and Mehran Kardar},
  journal= {arXiv preprint arXiv:1907.00018},
  year   = {2019}
}

Comments

RevTex, 12 pages, 13 figures