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arXiv 2112.03491physics.comp-phcs.LGphysics.chem-ph
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用于变分蒙特卡罗模拟的显式反对称化神经网络层

Explicitly antisymmetrized neural network layers for variational Monte Carlo simulation

University of California, Berkeley(加州大学伯克利分校);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室)

Jeffmin Lin, Gil Goldshlager, Lin Lin

AI总结:

本研究针对电子波函数反对称层表达能力难以衡量的问题,提出显式反对称化神经网络层,通过对比不同架构发现反对称乘积之和是FermiNet的关键限制,改进后的全单行列式FermiNet性能显著提升。

摘要:

神经网络与量子蒙特卡罗方法的结合已成为实现高精度电子结构计算的一条可行路径。此前的研究方案将等变神经网络层与反对称层相结合,以满足电子波函数的反对称性要求。但截至目前,人们尚不清楚能否表示出具有物理意义的反对称函数,且难以衡量反对称层的表达能力。本研究尝试通过引入显式反对称化通用神经网络层作为诊断工具来解决这一问题。我们首先提出了通用反对称(GA)层,用其替换高精度拟设FermiNet的整个反对称层。实验证明,由此得到的FermiNet-GA架构在小体系中可有效得到精确的基态能量。随后我们研究了因子化反对称(FA)层,该层通过将行列式乘积替换为反对称化神经网络乘积,更直接地对FermiNet进行推广。有趣的是,得到的FermiNet-FA架构性能并未超越FermiNet。这表明反对称乘积之和是FermiNet架构的关键限制因素。为进一步探究这一点,我们研究了对FermiNet的一处微小修改——全行列式模式,它将每个行列式乘积替换为单个组合行列式。全单行列式FermiNet大幅缩小了标准单行列式FermiNet与FermiNet-GA之间的差距。令人意外的是,在键长解离至4.0玻尔的氮分子体系中,全单行列式FermiNet的性能显著优于标准64行列式FermiNet,其能量与现有最优计算基准的差值在0.4 kcal/mol以内。

英文摘要:

The combination of neural networks and quantum Monte Carlo methods has arisen as a path forward for highly accurate electronic structure calculations. Previous proposals have combined equivariant neural network layers with an antisymmetric layer to satisfy the antisymmetry requirements of the electronic wavefunction. However, to date it is unclear if one can represent antisymmetric functions of physical interest, and it is difficult to measure the expressiveness of the antisymmetric layer. This work attempts to address this problem by introducing explicitly antisymmetrized universal neural network layers as a diagnostic tool. We first introduce a generic antisymmetric (GA) layer, which we use to replace the entire antisymmetric layer of the highly accurate ansatz known as the FermiNet. We demonstrate that the resulting FermiNet-GA architecture can yield effectively the exact ground state energy for small systems. We then consider a factorized antisymmetric (FA) layer which more directly generalizes the FermiNet by replacing products of determinants with products of antisymmetrized neural networks. Interestingly, the resulting FermiNet-FA architecture does not outperform the FermiNet. This suggests that the sum of products of antisymmetries is a key limiting aspect of the FermiNet architecture. To explore this further, we investigate a slight modification of the FermiNet called the full determinant mode, which replaces each product of determinants with a single combined determinant. The full single-determinant FermiNet closes a large part of the gap between the standard single-determinant FermiNet and FermiNet-GA. Surprisingly, on the nitrogen molecule at a dissociating bond length of 4.0 Bohr, the full single-determinant FermiNet can significantly outperform the standard 64-determinant FermiNet, yielding an energy within 0.4 kcal/mol of the best available computational benchmark.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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