论文标题
使用Block-Househoush-Thransformation进行多轨碎片的量子嵌入
Quantum embedding of multi-orbital fragments using the Block-Householder-transformation
论文作者
论文摘要
最近，一些作者介绍了将家庭转化用作嵌入局部分子片段的简单而直观的方法（参见Sekaran等人，Phys。Rev.B 104，035121（2021）和Sekaran等人，Sekaran等人，计算10，45（2022））。在这项工作中，我们将这种方法扩展到了更通用的多轨碎片案例，使用应用于单体降低密度矩阵的住户转换的块版本，但将适用性释放到通用量子化学/凝结的物理物理学汉密尔顿。 提出了一个逐步建设，逐步构建了座屋持有人转换。该方法的物理和数值兴趣都得到了强调。特定的平均场（非交互式）情况已彻底详细介绍，这表明给定的$ n $旋转轨道片段的嵌入导致产生两个分离的子系统：$ 2N $旋转轨道轨道“碎片+浴”集群，这些群集完全包含$ n $ n $ n $电子，以及剩余的群集“ core core core core core core core core core core core core core core core core core core core core core core core core core core core core core so-call so so corl so-call so-call。我们说明在嵌入{scheme}的不同情况下，用于实用应用的不同情况。我们特别关注先前引入的局部潜在功能嵌入理论（LPFET）和家庭转换密度矩阵功能嵌入理论（HT-DMFET）的扩展。这些计算是在不同类型的系统（例如Hamiltonians（Hubbard环）和\ textit {ab litio}分子系统（氢环）等不同类型的系统上实现的。
Recently, some of the authors introduced the use of the Householder transformation as a simple and intuitive method for the embedding of local molecular fragments (see Sekaran et. al., Phys. Rev. B 104, 035121 (2021), and Sekaran et. al., Computation 10, 45 (2022)). In this work, we present an extension of this approach to the more general case of multi-orbital fragments using the block version of the Householder transformation applied to the one-body reduced density matrix, yet unlocking the applicability to general quantum chemistry/condensed-matter physics Hamiltonians. A step by step construction of the Block-Householder transformation is presented. Both physical and numerical interest of the approach are highlighted. The specific mean-field (non-interacting) case is thoroughly detailed as it is shown that the embedding of a given $N$ spin-orbitals fragment leads to the generation of two separated sub-systems: a $2N$ spin-orbitals "fragment+bath" cluster that exactly contains $N$ electrons, and a remaining cluster's "environment" which is described by so-called core electrons. We illustrate the use of this transformation in different cases of embedding {scheme} for practical applications. We particularly focus on the extension of the previously introduced Local Potential Functional Embedding Theory (LPFET) and Householder-transformed Density Matrix Functional Embedding Theory (Ht-DMFET) to the case of multi-orbital fragments. These calculations are realized on different types of systems such as model Hamiltonians (Hubbard rings) and \textit{ab initio} molecular systems (hydrogen rings).
