Removing nodal and support-mismatch pathologies in Variational Monte Carlo via blurred sampling

Fuente: arXiv
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Main Authors: Wan, Zhou-Quan, Wiersema, Roeland, Zhang, Shiwei
Format: Preprint
Published: 2026
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author Wan, Zhou-Quan
Wiersema, Roeland
Zhang, Shiwei
author_facet Wan, Zhou-Quan
Wiersema, Roeland
Zhang, Shiwei
contents Variational Monte Carlo (VMC) is a powerful and fast-growing method for optimizing and evolving parameterized many-body wave functions, especially with modern neural-network quantum states. In practice, however, the stochastic estimators that form the backbone of the method can become unstable or biased due to the presence of nodes, a ubiquitous feature of quantum wave functions. In the continuum, this results in heavy-tailed estimators with potentially divergent variances, while in discrete Hilbert spaces the sampling distribution can miss parts of the support needed to form unbiased estimators. These statistical pathologies lead to unreliable optimization trajectories in stochastic reconfiguration or incorrect variational dynamics in time-dependent Variational Monte Carlo (t-VMC), and severely limit the power of the numerical simulations. We introduce blurred sampling to address these difficulties. The method has a number of rigorous properties that make it well-behaved, effective and efficient. Additionally it is a post-processing approach that can be used without modifying the underlying sampler and incurs only minimal overhead. We demonstrate its effectiveness on several representative examples where standard sampling approaches are known to fail, and apply it to large-scale problems in spin dynamics. This work establishes a broadly applicable framework for robust VMC and t-VMC calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2603_18148
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Removing nodal and support-mismatch pathologies in Variational Monte Carlo via blurred sampling
Wan, Zhou-Quan
Wiersema, Roeland
Zhang, Shiwei
Strongly Correlated Electrons
Disordered Systems and Neural Networks
Computational Physics
Quantum Physics
Variational Monte Carlo (VMC) is a powerful and fast-growing method for optimizing and evolving parameterized many-body wave functions, especially with modern neural-network quantum states. In practice, however, the stochastic estimators that form the backbone of the method can become unstable or biased due to the presence of nodes, a ubiquitous feature of quantum wave functions. In the continuum, this results in heavy-tailed estimators with potentially divergent variances, while in discrete Hilbert spaces the sampling distribution can miss parts of the support needed to form unbiased estimators. These statistical pathologies lead to unreliable optimization trajectories in stochastic reconfiguration or incorrect variational dynamics in time-dependent Variational Monte Carlo (t-VMC), and severely limit the power of the numerical simulations. We introduce blurred sampling to address these difficulties. The method has a number of rigorous properties that make it well-behaved, effective and efficient. Additionally it is a post-processing approach that can be used without modifying the underlying sampler and incurs only minimal overhead. We demonstrate its effectiveness on several representative examples where standard sampling approaches are known to fail, and apply it to large-scale problems in spin dynamics. This work establishes a broadly applicable framework for robust VMC and t-VMC calculations.
title Removing nodal and support-mismatch pathologies in Variational Monte Carlo via blurred sampling
topic Strongly Correlated Electrons
Disordered Systems and Neural Networks
Computational Physics
Quantum Physics
url https://arxiv.org/abs/2603.18148