Matrix Product States with Large Sites
Matrix Product States with Large Sites
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DOI：
10.1021/acs.jctc.1c00957
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发表时间：
2022-01-21
影响因子：
5.5
通讯作者：
Chan, Garnet Kin-Lic
中科院分区：
文献类型：
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作者：
Larsson, Henrik R.;Zhai, Huanchen;Chan, Garnet Kin-Lic
我们探索了在矩阵积态（MPS）中将轨道分组成簇的各种方法。我们解释了一个通用的簇MPS如何经常导致计算成本的增加，并提出了一种特殊的簇结构，只涉及第一和最后轨道/位点，具有更广泛的计算优势。这种结构是描述相关多参考理论的自然形式。我们通过使用具有大簇位的MPS实现各种非收缩MR配置相互作用、摄动和线性化耦合簇理论，证明了这种方法的灵活性和实用性。氮二聚体、铬二聚体和苯的应用，包括在外部空间的三重激发，证明了MPS具有最多两个大位点的实用性。我们用我们的结果来分析不同的多参考近似的质量。
We explore various ways to group orbitals into clusters in a matrix product state (MPS). We explain how a generic cluster MPS can often lead to an increase in computational cost and instead propose a special cluster structure, involving only the first and last orbitals/sites, with a wider scope for computational advantage. This structure is a natural formalism to describe correlated multireference (MR) theories. We demonstrate the flexibility and usefulness of this approach by implementing various uncontracted MR configuration interaction, perturbation, and linearized coupled cluster theories using an MPS with large cluster sites. Applications to the nitrogen dimer, the chromium dimer, and benzene, including up to triple excitations in the external space, demonstrate the utility of an MPS with up to two large sites. We use our results to analyze the quality of different multireference approximations.