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arXiv 2008.03907cond-mat.str-el
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一维哈伯德模型中的例外点

Exceptional points in the one-dimensional Hubbard model

Roman Rausch, Robert Peters, Tsuneya Yoshida

摘要:

非厄米特现象提供了一种新的方法来分析和解释光谱中存在的相互作用。利用密度矩阵重整化群(DMRG),我们证明了具有手征对称性的一维交替Hubbard链的单粒子格林函数存在例外点,并在谱中的零频率处存在相应的费米弧.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,并且只出现在有限温度下。它们是鲁棒的,并且可以用第零个Chern数来拓扑刻画。这种效应说明了一种情况下,温度有一个强大的影响,在1D超出了简单的扩大光谱特征。最后,我们证明,例外点出现,即使在两粒子格林函数(电荷结构因子),有效的哈密顿量是难以建立,但远离零频率,由于一个独特的对称性约束。

英文摘要:

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.

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。

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