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arXiv 2202.08709physics.chem-phcond-mat.str-elphysics.atom-phphysics.comp-ph
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用互关联矩阵乘积算符计算关联电子结构

Explicitly correlated electronic structure calculations with transcorrelated matrix product operators

Alberto Baiardi, Michał Lesiuk, Markus Reiher

摘要:

在这项工作中,我们提出的第一个实现的互关联电子哈密顿矩阵乘积态的密度矩阵重整化群(DMRG)算法的优化过程。在互相关分析中,电子哈密顿量被用一个Jastrow因子进行相似变换,以描述电子-电子合并时波函数中的尖点。结果表明,用单粒子基函数和Slater行列式的常规展开式更容易精确地近似波函数。在第一个量子化的互相关哈密顿量包括三体相互作用,我们处理的标准方式,通过应用强大的密度拟合的两个和三体积分进入第二个量子化表示的这个哈密顿量。通过将其编码为矩阵乘积算子并利用时间依赖于时间的DMRG优化相应的基态波函数,沿着关于互相关DMRG的第一项工作[J. Chem. Phys. 153,164115(2020)]的路线来处理互相关哈密顿量的厄米性的缺乏。我们展示了我们的量子化学互相关DMRG方法的例子中的几个原子和第一排双原子分子。我们表明,互相关提高了收敛速度的完整的基组限制相比,传统的DMRG。此外,我们研究扩展我们的方法,旨在减少处理的矩阵乘积算子表示的互相关哈密顿的成本。

英文摘要:

In this work, we present the first implementation of the transcorrelated electronic Hamiltonian in an optimization procedure for matrix product states by the density matrix renormalization group (DMRG) algorithm. In the transcorrelation ansatz, the electronic Hamiltonian is similarity-transformed with a Jastrow factor to describe the cusp in the wave function at electron-electron coalescence. As a result, the wave function is easier to approximate accurately with the conventional expansion in terms of one-particle basis functions and Slater determinants. The transcorrelated Hamiltonian in first quantization comprises up to three-body interactions, which we deal with in the standard way by applying robust density fitting to two- and three-body integrals entering the second-quantized representation of this Hamiltonian. The lack of hermiticity of the transcorrelated Hamiltonian is taken care of along the lines of the first work on transcorrelated DMRG [J. Chem. Phys. 153, 164115 (2020)] by encoding it as a matrix product operator and optimizing the corresponding ground state wave function with imaginary-time time-dependent DMRG. We demonstrate our quantum chemical transcorrelated DMRG approach at the example of several atoms and first-row diatomic molecules. We show that transcorrelation improves the convergence rate to the complete basis set limit in comparison to conventional DMRG. Moreover, we study extensions of our approach that aim at reducing the cost of handling the matrix product operator representation of the transcorrelated Hamiltonian.

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