arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2109.05129cond-mat.str-elquant-ph
收藏

用切片基DMRG构造氢链的哈伯德模型

Constructing Hubbard Models for the Hydrogen Chain using Sliced Basis DMRG

Randy C. Sawaya, Steven R. White

摘要:

采用切片基DMRG(sb-DMRG)模拟氢原子链,构造低能有效的Hubbard类模型.向下折叠的过程首先涉及到一组原子为中心的Wannier函数的基础的变化构造的自然轨道的精确DMRG单粒子密度矩阵。然后将Wannier函数模型简化为少参数的Hubbard模型,其参数由Hubbard哈密顿量在基态的Wannier哈密顿量的期望值最小化确定.这种间接的变分方法不仅产生紧凑和简单的模型的氢链,但也使我们能够探索的重要性,有效的哈密顿量的约束,如限制的范围内的单粒子跳跃和两个粒子的相互作用,并评估更传统的向下折叠的可靠性。模型的基态的纠缠熵是决定DMRG和张量网络模拟模型的能力的一个重要属性,我们研究了它随相互作用范围的变化。与直觉相反,我们发现较短距离的相互作用往往有较大的纠缠。

英文摘要:

Sliced-basis DMRG(sb-DMRG) is used to simulate a chain of hydrogen atoms and to construct low-energy effective Hubbard-like models. The downfolding procedure first involves a change of basis to a set of atom-centered Wannier functions constructed from the natural orbitals of the exact DMRG one-particle density matrix. The Wannier function model is then reduced to a fewer-parameter Hubbard-like model, whose parameters are determined by minimizing the expectation value of the Wannier Hamiltonian in the ground state of the Hubbard Hamiltonian. This indirect variational procedure not only yields compact and simple models for the hydrogen chain, but also allows us to explore the importance of constraints in the effective Hamiltonian, such as the restricting the range of the single-particle hopping and two-particle interactions, and to assess the reliability of more conventional downfolding. The entanglement entropy for a model's ground state, cut in the middle, is an important property determining the ability of DMRG and tensor networks to simulate the model, and we study its variation with the range of the interactions. Counterintuitively, we find that shorter ranged interactions often have larger entanglement.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑