Strict inequality for bond percolation on a dilute lattice with columnar disorder

Abstract

We consider a dilute lattice obtained from the usual $\mathbb{Z}^3$ lattice by removing independently each of its columns with probability $1-\rho$. In the remaining dilute lattice independent Bernoulli bond percolation with parameter $p$ is performed. Let $\rho \mapsto p_c(\rho)$ be the critical curve which divides the subcritical and supercritical phases. We study the behavior of this curve near the disconnection threshold $\rho_c = p_c^{\text{site}}(\mathbb{Z}^2)$ and prove that, uniformly over $\rho$ it remains strictly below $1/2$ (the critical point for bond percolation on the square lattice $\mathbb{Z}^2)$.