Monte Carlo methods on compact complex manifolds using Bergman kernels
Thibaut Lemoine, Rémi Bardenet
TL;DR
This work introduces a Bergman-ensemble Monte Carlo method for numerical integration on compact complex manifolds by sampling nodes from a determinantal point process with Bergman kernel. The estimator, formed by weighting function values with the inverse diagonal kernel, is unbiased for the target measure and satisfies a central limit theorem with a rate tied to the complex dimension, yielding a mean-square error decay of $N^{-1-2/d_{\real}}$ where $d_{\real}=2d$. The main contribution is a universal CLT for these DPP-based estimators, matching the Bak lower bound for $\mathscr{C}^1$-class functions in Euclidean spaces and showing improved performance over prior DPP-based quadratures. The paper provides detailed kernel estimates, a rigorous proof of the MC_main theorem, and a concrete Riemann-sphere application with numerical experiments, illustrating practical efficacy and potential extensions to broader manifolds.
Abstract
In this paper, we propose a new randomized method for numerical integration on a compact complex manifold with respect to a continuous volume form. Taking for quadrature nodes a suitable determinantal point process, we build an unbiased Monte Carlo estimator of the integral of any Lipschitz function, and show that the estimator satisfies a central limit theorem, with a faster rate than under independent sampling. In particular, seeing a complex manifold of dimension $d$ as a real manifold of dimension $d_{\mathbb{R}}=2d$, the mean squared error for $N$ quadrature nodes decays as $N^{-1-2/d_{\mathbb{R}}}$; this is faster than previous DPP-based quadratures and reaches the optimal worst-case rate investigated by [Bakhvalov 1965] in Euclidean spaces. The determinantal point process we use is characterized by its kernel, which is the Bergman kernel of a holomorphic Hermitian line bundle, and we strongly build upon the work of Berman that led to the central limit theorem in [Berman, 2018].We provide numerical illustrations for the Riemann sphere.
