Exceptional points in the one-dimensional Hubbard model
Exceptional points in the one-dimensional Hubbard model
复制标题
一维哈伯德模型中的例外点
DOI：
10.1088/1367-2630/abd35e
复制
发表时间：
2021
影响因子：
3.3
通讯作者：
Yoshida Tsuneya
中科院分区：
文献类型：
--
作者：
Rausch Roman;Peters Robert;Yoshida Tsuneya
非厄米现象提供了一种新的方法来分析和解释光谱在相互作用的存在。利用密度矩阵重整化群（DMRG），我们证明了具有手性对称的一维交替Hubbard链的单粒子格林函数的异常点的存在性，并在谱中的零频率处有相应的费米弧。它们是由描述格林函数的有效哈密顿量的非厄米性引起的，并且只在有限温度下出现。它们具有鲁棒性，可以用第零陈氏数来拓扑表征。这种效应说明了温度在一维中除了光谱特征的简单展宽外，还有很强的影响。最后，我们证明了异常点甚至出现在两粒子格林函数（电荷结构因子）中，其中有效哈密顿量难以建立，但由于明显的对称性约束而远离零频率。
Non-Hermitian phenomena offer a novel approach to analyze and interpret spectra in the presence of interactions. Using the density-matrix renormalization group (DMRG), we demonstrate the existence of exceptional points for the one-particle Green's function of the 1D alternating Hubbard chain with chiral symmetry, with a corresponding Fermi arc at zero frequency in the spectrum. They result from the non-Hermiticity of the effective Hamiltonian describing the Green's function and only appear at finite temperature. They are robust and can be topologically characterized by the zeroth Chern number. This effect illustrates a case where temperature has a strong effect in 1D beyond the simple broadening of spectral features. Finally, we demonstrate that exceptional points appear even in the two-particle Green's function (charge structure factor) where an effective Hamiltonian is difficult to establish, but move away from zero frequency due to a distinct symmetry constraint.