Critical one-arm probability for the metric Gaussian free field in low dimensions

TL;DR

This paper studies the critical one-arm probability decay in the Gaussian free field's excursion sets on low-dimensional graphs, extending known formulas and providing decay rate estimates for specific cases like =^3.

Contribution

It extends Lupu's formula for the two-point function at criticality and derives decay rates for the critical one-arm probability in low-dimensional settings.

Findings

Critical one-arm probability decays as R^{- u/2} in low dimensions.

Extension of Lupu's formula to new settings.

Application to =^3 case with explicit decay rate.

Abstract

We investigate the bond percolation model on transient weighted graphs ${G}$ induced by the excursion sets of the Gaussian free field on the corresponding metric graph. Under the sole assumption that its sign clusters do not percolate, we derive an extension of Lupu's formula for the two-point function at criticality. We then focus on the low-dimensional case $0< \nu < \frac{\alpha}{2}$, where $\alpha$ governs the polynomial volume growth of $G$ and $\nu$ the decay rate of the Green's function on $G$. In particular, this includes the benchmark case ${G}=\mathbb{Z}^3$, for which $\alpha=3$ and $\nu= \alpha-2=1$. We prove under these assumptions that the critical one-arm probability decays with distance $R$ like $R^{-\frac{\nu}{2}}$, up to multiplicative constants.