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arXiv 2203.11902cond-mat.mes-hall
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一维非厄米链中的电极化的强度及其量子化

Electric polarization and its quantization in one-dimensional non-Hermitian chains

Jinbing Hu, Carmine Antonio Perroni, Giulio De Filippis, Songlin Zhuang, Lorenzo Marrucci, Filippo Cardano

摘要:

本文将现代电极化的强度理论推广到一维非厄米系统的线隙谱情形。在这些系统中,电子位置算符是非厄米的,即使当投影到低于能隙的状态的子空间。然而,相关的威尔逊回路运营商是biorthogonally单一的热力学极限,从而导致实值电子的位置,允许一个干净的定义极化。非厄米极化可以在某些对称性的存在下量子化,如厄米绝缘体。然而,与后一种情况不同的是,在这种情况下,极化量子化还取决于能隙的类型,它可以是实的或虚的,从而导致更丰富的拓扑相位。最反直觉的例子是仅具有时间反演对称性的1D非厄米链,其中非厄米极化在存在假想线隙的情况下被量子化。我们提出了两个具体的模型,以提供支持我们的研究结果的数值证据。

英文摘要:

We generalize the modern theory of electric polarization to the case of one-dimensional non-Hermitian systems with line-gapped spectrum. In these systems, the electronic position operator is non-Hermitian even when projected into the subspace of states below the energy gap. However, the associated Wilson-loop operator is biorthogonally unitary in the thermodynamic limit, thereby leading to real-valued electronic positions that allow for a clean definition of polarization. Non-Hermitian polarization can be quantized in the presence of certain symmetries, as for Hermitian insulators. Different from the latter case, though, in this regime polarization quantization depends also on the type of energy gap, which can be either real or imaginary, leading to a richer variety of topological phases. The most counter-intuitive example is the 1D non-Hermitian chain with time-reversal symmetry only, where non-Hermitian polarization is quantized in presence of an imaginary line-gap. We propose two specific models to provide numerical evidence supporting our findings.

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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