Coupled Cluster and Perturbation Theories Based on a Cluster Mean-Field Reference Applied to Strongly Correlated Spin Systems.
Coupled Cluster and Perturbation Theories Based on a Cluster Mean-Field Reference Applied to Strongly Correlated Spin Systems.
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DOI：
10.1021/acs.jctc.2c00338
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发表时间：
2021-02
影响因子：
5.5
通讯作者：
Athanasios Papastathopoulos-Katsaros;C. Jiménez-Hoyos;T. M. Henderson;G. Scuseria
中科院分区：
文献类型：
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作者：
Athanasios Papastathopoulos-Katsaros;C. Jiménez-Hoyos;T. M. Henderson;G. Scuseria
我们引入了基于团簇平均场参考的微扰和耦合团簇理论来描述强相关自旋系统的基态。在簇平均场中，基态波函数被写成优化簇态的简单张量积。聚类语言和ansatz的平均场性质允许使用微扰理论和耦合聚类来解释聚类间相关性的直接改进。利用聚类平均场、微扰理论和耦合聚类，对一维链和二维方形J1-J2海森堡模型进行了基准计算。我们还提出了一个外推方案，使我们能够准确地计算热力学极限能量。我们的研究结果表明，在足够大的聚类下，相关方法（cPT2、cPT4和cCCSD）可以相对准确地描述所考虑的体系中的海森堡模型，这表明所提出的方法可以用于其他强相关系统。讨论了改进本工作中提出的方法的一些方法。
We introduce perturbation and coupled-cluster theories based on a cluster mean-field reference for describing the ground state of strongly correlated spin systems. In cluster mean-field, the ground state wave function is written as a simple tensor product of optimized cluster states. The cluster language and the mean-field nature of the ansatz allow for a straightforward improvement which uses perturbation theory and coupled-cluster to account for intercluster correlations. We present benchmark calculations on the 1D chain and 2D square J1-J2 Heisenberg model, using cluster mean-field, perturbation theory, and coupled-cluster. We also present an extrapolation scheme that allows us to compute thermodynamic limit energies accurately. Our results indicate that, with sufficiently large clusters, the correlated methods (cPT2, cPT4, and cCCSD) can provide a relatively accurate description of the Heisenberg model in the regimes considered, which suggests that the methods presented can be used for other strongly correlated systems. Some ways to improve upon the methods presented in this work are discussed.