Polyharmonic Fields and Liouville Quantum Gravity Measures on Tori of Arbitrary Dimension: from Discrete to Continuous

TL;DR

This paper establishes the convergence of discrete polyharmonic Gaussian fields and associated Liouville quantum gravity measures on tori of arbitrary dimension to their continuous counterparts, extending the understanding of these fields in higher dimensions.

Contribution

It introduces a framework for analyzing polyharmonic Gaussian fields and Liouville quantum gravity measures on high-dimensional tori, proving their convergence from discrete to continuous settings.

Findings

Discrete fields converge to continuous polyharmonic Gaussian fields.

Associated measures converge to Liouville quantum gravity measures.

Results hold for all regularity parameters within a specified range.

Abstract

For an arbitrary dimension $n$, we study: (a) the Polyharmonic Gaussian Field $h_L$ on the discrete torus $\mathbb{T}^n_L = \frac{1}{L} \mathbb{Z}^{n} / \mathbb{Z}^{n}$, that is the random field whose law on $\mathbb{R}^{\mathbb{T}^{n}_{L}}$ given by \begin{equation*} c_n\, e^{-b_n\|(-\Delta_L)^{n/4}h\|^2} dh, \end{equation*} where $dh$ is the Lebesgue measure and $\Delta_{L}$ is the discrete Laplacian; (b) the associated discrete Liouville Quantum Gravity measure associated with it, that is the random measure on $\mathbb{T}^{n}_{L}$ \begin{equation*}\mu_{L}(dz) = \exp \Big( \gamma h_L(z) - \frac{\gamma^{2}}{2} \mathbf{E} h_{L}(z) \Big) dz,\end{equation*} where $\gamma$ is a regularity parameter. As $L\to\infty$, we prove convergence of the fields $h_L$ to the Polyharmonic Gaussian Field $h$ on the continuous torus $\mathbb{T}^n = \mathbb{R}^{n} / \mathbb{Z}^{n}$, as well as convergence of the random measures $\mu_L$ to the LQG measure $\mu$ on $\mathbb{T}^n$, for all $|\gamma| < \sqrt{2n}$.