arXiv:2511.01671physics.chem-phcs.AI2025-11被引 3

用群表示论让神经网络波函数精确满足自旋对称性,提升电子关联计算精度。

Spin-Adapted Neural Network Wavefunctions in Real Space

  • 基于群表示论设计自旋适应机制,确保波函数严格满足总自旋对称性
  • 在铁硫簇上准确解析低能自旋态与自旋间隙,优于现有方法
  • 无需额外超参数,适合强关联体系的高精度量子蒙特卡洛模拟

自旋在电子结构理解中起根本作用,但许多实空间波函数方法未能充分考虑其影响。我们提出自旋适应反称化方法(SAAM),一种在实空间中对多电子反对称波函数强制实现精确总自旋对称性的通用框架。在基于神经网络的量子蒙特卡洛(NNQMC)背景下,SAAM利用深度神经网络的表达能力捕捉电子关联,同时通过群表示论精确实现自旋适应。该框架为原本黑箱化的神经网络波函数嵌入物理先验提供了合理路径,实现了以神经网络轨道表示相关体系的紧凑形式。相较于现有NNQMC中的自旋处理方式,SAAM更准确且高效,实现精确自旋纯度而无需额外可调超参数。我们将其应用于铁硫簇的自旋阶梯研究,这是多体方法长期面临的挑战,因其存在密集的近简并自旋态谱。结果揭示了[Fe₂S₂]和[Fe₄S₄]簇中低能自旋态与自旋间隙的精确分辨,为它们的电子结构提供了新见解。综上,这些成果确立了SAAM作为自旋适应型NNQMC的稳健、无超参数标准,尤其适用于强关联体系。

原文摘要 · Abstract (English)

Spin plays a fundamental role in understanding electronic structure, yet many real-space wavefunction methods fail to adequately consider it. We introduce the Spin-Adapted Antisymmetrization Method (SAAM), a general procedure that enforces exact total spin symmetry for antisymmetric many-electron wavefunctions in real space. In the context of neural network-based quantum Monte Carlo (NNQMC), SAAM leverages the expressiveness of deep neural networks to capture electron correlation while enforcing exact spin adaptation via group representation theory. This framework provides a principled route to embed physical priors into otherwise black-box neural network wavefunctions, yielding a compact representation of correlated system with neural network orbitals. Compared with existing treatments of spin in NNQMC, SAAM is more accurate and efficient, achieving exact spin purity without any additional tunable hyperparameters. To demonstrate its effectiveness, we apply SAAM to study the spin ladder of iron-sulfur clusters, a long-standing challenge for many-body methods due to their dense spectrum of nearly degenerate spin states. Our results reveal accurate resolution of low-lying spin states and spin gaps in [Fe$_2$S$_2$] and [Fe$_4$S$_4$] clusters, offering new insights into their electronic structures. In sum, these findings establish SAAM as a robust, hyperparameter-free standard for spin-adapted NNQMC, particularly for strongly correlated systems.

量子蒙特卡洛神经网络波函数自旋适应强关联体系

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