Optimizing Hartree-Fock orbitals by the density-matrix renormalization group

Constrained-Pairing Mean-Field Theory. IV. Inclusion of corresponding pair constraints and connection to unrestricted Hartree-Fock theory

Our previously developed Constrained-Pairing Mean-Field Theory (CPMFT) is shown to map onto an Unrestricted Hartree-Fock (UHF) type method if one imposes a corresponding pair constraint to the correlation problem that forces occupation numbers to occur in pairs adding to 1. In this new version, CPMFT has all the advantages of standard independent particle models (orbitals and orbital energies, to mention a few), yet unlike UHF, it can dissociate polyatomic molecules to the correct ground-state restricted open-shell Hartree-Fock atoms or fragments.

均匀电子气中金属相的存在性和Hartree-Fock能量的上界

Existence of a metallic phase and upper bounds of the Hartree-Fock energy in the homogeneous electron gas

我们考虑均匀电子气的基态，我们证明了一个Hartree-Fock解决方案，由以前的模拟的动机，具有较低的能量比费米气体在大密度限制。这种溶液是金属相：密度调制对应于部分占据的晶体（位置数大于电子数）。

Matrix product states for Hartree-Fock-Bogoliubov wave functions

We provide an efficient and accurate method for converting Hartree-Fock-Bogoliubov wave functions into matrix product states (MPSs). These wave functions, also known as Bogoliubov vacua, exhibit a peculiar entanglement structure that the eigenvectors of the reduced density matrix are also Bogoliubov vacua. We exploit this important feature to obtain their optimal MPS approximation and derive an explicit formula for corresponding MPS matrices. The performance of our method is benchmarked with the Kitaev chain and the Majorana-Hubbard model on the honeycomb lattice. The approach facilitates the …

Projected Hartree-Fock as a Polynomial of Particle-Hole Excitations and Its Combination With Variational Coupled Cluster Theory

Projected Hartree-Fock theory provides an accurate description of many kinds of strong correlation but does not properly describe weakly correlated systems. Coupled cluster theory, in contrast, does the opposite. It therefore seems natural to combine the two so as to describe both strong and weak correlations with high accuracy in a relatively black-box manner. Combining the two approaches, however, is made more difficult by the fact that the two techniques are formulated very differently. In earlier work, we showed how to write spin-projected Hartree-Fock in a coupled-cluster-like language. H…

Properties of Hartree-Fock solutions of the three-dimensional electron gas

In a previous letter, L. Baguet et al., (Phys. Rev. Lett. {\bf 111}, 166402 (2013)), we presented the ground state phase diagram of the homogeneous electron gas in three dimensions within the Hartree-Fock approximation yielding incommensurate crystal states at high density. Here, we analyze the properties of these solutions. In particular, at high density we find universal behavior of the incommensurate crystal strongly supporting the existence of a spin density wave ground state.

量子库仑玻璃- Hartree-Fock近似与精确对角化

Quantum Coulomb glass - Hartree-Fock approximation versus exact diagonalization

我们研究了无序相互作用电子在绝缘区的行为。我们的研究是基于量子库仑玻璃模型，该模型是在经典库仑玻璃的基础上，通过在相邻格点之间加入跳跃矩阵元而得到的。我们使用两种不同的数值方法，即Hartree-Fock近似和精确对角化，并比较结果的隧穿态密度和本地化属性，以确定的Hartree-Fock方法的有效性范围。我们发现，Hartree-Fock方法给出了一个很好的近似的所有能量的态密度，但代表的本地化属性正确接近费米能级。无序相互作用的电子的本地化的一些后果进行了讨论。

基于含时Hartree-Fock计算的顺电-铁电交叉和电子动力学

Paraelectric-to-ferroelectric crossover and electron dynamics from time-dependent Hartree-Fock calculations

近年来，研究人员发现了具有结构顺序不同于原始顺序的激发畴的电子的各种激发态。利用含时Hartree-Fock近似研究了电子系统和声子系统的动力学。我们研究了自旋自由度的时间演化。我们发现了一个热激发的顺电-铁电交叉。亚稳态是自旋皮尔斯态。我们还研究了四分之一充满时电子系统的朗道展开。

Quantum quenches and competing orders: I. Time-dependent Hartree-Fock+BCS theory

We study the non-equlibrium dynamics of an electronic model of competing bond density wave order and $d$-wave superconductivity. In a time-dependent Hartree-Fock+BCS approximation, the dynamics reduces to the equations of motion of operators realizing the generators of SU(4) at each pair of momenta, $(\boldsymbol{k}, -\boldsymbol{k})$, in the Brillouin zone. We compare the results of numerical studies of our model with recent picosecond optical experiments.

二维 Hubbard 模型 Hartree-Fock 方法的一种变分改进

A Variational Improvement of the Hartree-Fock Approach to the 2D Hubbard Model

本文在 Nambu 旋量 Hartree-Fock 框架中引入含变分参数 h 的诱导凝聚项生成试探态，发现非均匀条纹相中存在能量更低的 s/d 波凝聚态。

量子点中的自旋和相互作用效应：Hartree-Fock-Koopmans方法

Spin and interaction effects in quantum dots: a Hartree-Fock-Koopmans approach

我们使用Hartree-Fock-Koopmans方法研究了扩散或混沌量子点中的自旋和相互作用效应。特别是，我们推导出连续库仑阻塞峰之间的间距的统计。我们包括两体屏蔽相互作用，表面电荷势和限制势的矩阵元素的波动，以领先的顺序在逆无源电导。计算的峰间距分布与实验结果进行了比较。

量子点接触电导的限制和非限制Hartree-Fock计算

Restricted and unrestricted Hartree-Fock calculations of conductance for a quantum point contact

非常短的量子线（量子接触）在接近$0.7 \times 2e^2/h$的电导值处呈现电导结构。据信，该结构是由于电子-电子相互作用而产生的，并且它也与电子自旋有关。然而，该结构的机制的细节并不十分清楚。以前，我们处理的问题内的限制Hartree-Fock近似。该计算证明了与实验观察到的结构相似的结构。在目前的工作中，我们进行限制和无限制的Hartree-Fock计算分析的有效性的近似。我们还考虑了铅中的电子密度的影响的依赖性。不受限制的Hartree-Fock方法使我们能够分析接触中单个电子的捕获。这样的陷阱将导致“0.7结构”的Kondo模型。目前的计算证实了自旋相关的束缚态图片，并没有确认近藤模型的情况。