Tensor product expansions for correlation in quantum many-body systems
Tensor product expansions for correlation in quantum many-body systems
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DOI：
10.1103/physrevb.61.7348
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发表时间：
2000-03-15
影响因子：
3.7
通讯作者：
Arias, TA
中科院分区：
文献类型：
--
作者：
Csányi, G;Arias, TA
我们探索了一类计算上可行的二体密度矩阵近似为单粒子算子张量积的有限和。然后，物理对称性用单体矩阵唯一地确定了二体矩阵。将动力相关性单独表示为单个张量积，可以得到一个理论，该理论预测中高密度均匀电子气体中的动力相关性接近于零。但是，将动态和统计相关效应作为张量积表示在一起会导致最近提出的“自然轨道泛函”。“我们发现后一种理论具有与已建立的多体理论一致的一些渐近性质，但在描述固体价区密度范围内的均匀电子气体时，并不比Hartree-Fock更准确。
We explore a class of computationally feasible approximations of the two-body density matrix as a finite sum of tensor products of single-particle operators. Physical symmetries then uniquely determine the two-body matrix in terms of the one-body matrix. Representing dynamical correlation alone as a single tensor product results in a theory that predicts near zero dynamical correlation in the homogeneous electron gas at moderate to high densities. But, representing both dynamical and statistical correlation effects together as a tensor product leads to the recently proposed ''natural orbital functional.'' We find that this latter theory has some asymptotic properties consistent with established many-body theory but is no more accurate than Hartree-Fock in describing the homogeneous electron gas for the range of densities typically found in the valence regions of solids.