English

Existence of an intermediate phase for oriented percolation

Probability 2012-02-08 v3 Mathematical Physics math.MP

Abstract

We consider the following oriented percolation model of N×Zd\mathbb {N} \times \mathbb{Z}^d: we equip N×Zd\mathbb {N}\times \mathbb{Z}^d with the edge set {[(n,x),(n+1,y)]nN,x,yZd}\{[(n,x),(n+1,y)] | n\in \mathbb {N}, x,y\in \mathbb{Z}^d\}, and we say that each edge is open with probability pf(yx)p f(y-x) where f(yx)f(y-x) is a fixed non-negative compactly supported function on Zd\mathbb{Z}^d with zZdf(z)=1\sum_{z\in \mathbb{Z}^d} f(z)=1 and p[0,inff1]p\in [0,\inf f^{-1}] is the percolation parameter. Let pcp_c denote the percolation threshold ans ZNZ_N the number of open oriented-paths of length NN starting from the origin, and study the growth of ZNZ_N when percolation occurs. We prove that for if d5d\ge 5 and the function ff is sufficiently spread-out, then there exists a second threshold pc(2)>pcp_c^{(2)}>p_c such that ZN/pNZ_N/p^N decays exponentially fast for p(pc,pc(2))p\in(p_c,p_c^{(2)}) and does not so when p>pc(2)p> p_c^{(2)}. The result should extend to the nearest neighbor-model for high-dimension, and for the spread-out model when d=3,4d=3,4. It is known that this phenomenon does not occur in dimension 1 and 2.

Keywords

Cite

@article{arxiv.1201.4552,
  title  = {Existence of an intermediate phase for oriented percolation},
  author = {Hubert Lacoin},
  journal= {arXiv preprint arXiv:1201.4552},
  year   = {2012}
}

Comments

16 pages, 2 figures, further typos corrected, enlarged intro and bibliography

R2 v1 2026-06-21T20:08:05.433Z