An improved upper bound for critical value of the contact process on ${\mathbb{Z}}^d$ with $d\ge 3$

Abstract

In this paper we give an improved upper bound for critical value ${\lambda }_c$ of the basic contact process on the lattice ${\mathbb{Z}}^d$ with $d\ge 3$. As a direct corollary of out result, \[ λ_c\leq 0.384. \] when $d=3$.

9 pages