用专家混合框架提升原子模拟速度,兼顾精度与稳定性。
Mixture of Experts Framework in Machine Learning Interatomic Potentials for Atomistic Simulations

- 按化学复杂度分区部署不同能力模型,动态分配计算资源。
- 共训练使多模型在边界处能量和力一致,避免人为应力场。
- 在铂-一氧化碳催化系统上实现超2倍加速,精度媲美高保真模拟。
第一性原理原子模拟对理解复杂材料现象至关重要,但受限于计算成本。机器学习势函数(MLIPs)虽大幅降低计算开销,其推理成本仍是大规模系统或长时间模拟的瓶颈。为此,我们提出基于E(3)等变Allegro架构的多保真度“专家混合”框架。该方法将模拟区域划分为化学复杂区(如反应界面)和简单区(如体相晶格),分别分配不同容量的模型。静态区域划分中,模型间机械不匹配尤为关键,易引发人工应力场和系统失稳。我们通过共训练策略解决:损失函数包含一致性约束——对共享体相环境下的原子能量和力差异施加惩罚,强制独立模型学习一致的体相物理描述。在真实的铂-一氧化碳催化体系上验证,共训练模型保持精确能量守恒,体相力学响应(如物态方程、体模量)高度一致,预测精度接近全高保真模拟,且计算速度提升两倍以上。
原文摘要 · Abstract (English)
First-principles atomistic simulations are essential for understanding complex material phenomena but are fundamentally limited by their computational cost. While Machine Learning Interatomic Potentials (MLIPs) have drastically improved cost for a given accuracy, their inference cost remains a bottleneck for massive systems or long timescales. To address this, we introduce a multifidelity "Mixture-of-Experts" framework based on the E(3)-equivariant Allegro architecture. Our method spatially partitions the simulation domain into a chemically complex region (e.g., reactive interfaces) and a simple region (e.g., bulk lattice), assigning models of varying capacity to each. Among the challenges in such static domain decomposition, the mechanical mismatch between models at the interface is particularly critical, as it can generate artificial stress fields and instability. We address this challenge with a co-training strategy in which the loss function includes agreement constraints -- penalties on per-atom energy and force discrepancies between models evaluated on shared bulk environments -- forcing the independent models to learn a consistent physical description of the bulk material. We validate this approach on a realistic Pt+CO catalytic system, demonstrating that the co-trained models maintain exact energy conservation, align their bulk mechanical response (e.g., equation of state and bulk modulus), and achieve predictive accuracy comparable to a full high-fidelity simulation at more than twice the computational speed.
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