One-arm exponents of high-dimensional percolation revisited
Diederik van Engelenburg, Christophe Garban, Romain Panis, Franco Severo
TL;DR
The paper proves, for $d>6$ and large spread $L$, that the one-arm probability at criticality decays as $\mathbb{P}_{p_c}[0\leftrightarrow\Lambda_n^c] \asymp n^{-2}$ in full-space and $\mathbb{P}_{p_c}[0\leftrightarrow_{\mathbb{H}}\Lambda_n^c] \asymp n^{-3}$ in the half-space for spread-out percolation. It achieves this with a streamlined, lace-expansion-free approach that hinges on the entropic bound of Dewan and Muirhead, together with sharp near-critical inputs for the susceptibility and a novel correlation-length notion $L(p)$ (and $\tilde L(p)$) from Dumínil-Copin and Panis. The method yields a robust, self-contained proof of the Kozma–Nachmias result in full-space and the Chatterjee–Hanson half-space exponent, and it also underpins a complementary half-space two-point function analysis, all while aligning with related high-dimensional Ising model techniques. This provides a practical, adaptable framework for mean-field-type exponent calculations in high-dimensional percolation and related models, without recourse to lace expansions.
Abstract
We consider sufficiently spread-out Bernoulli percolation in dimensions ${d>6}$. We present a short and simple proof of the up-to-constants estimate for the one-arm probability in both the full-space and half-space settings. These results were previously established by Kozma and Nachmias and by Chatterjee and Hanson, respectively. Our proof improves upon the entropic technique introduced by Dewan and Muirhead, relying on a sharp estimate on a suitably chosen correlation length recently obtained by Duminil-Copin and Panis. This approach is inspired by our companion work, where we compute the one-arm exponent for several percolation models related to the high-dimensional Ising model.
