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arXiv 2005.12608cond-mat.mes-hallcond-mat.supr-con
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平方根拓扑绝缘体和超导体的系统构造

Systematic construction of square-root topological insulators and superconductors

Motohiko Ezawa

摘要:

本文提出了一种基于图论构造描述原哈密顿量$H_{\text{original}}$平方根的哈密顿量$H_{\text{root}}$的一般方案。在$H_{\text{original}}$的原图的剖分图上定义了平方根哈密尔顿算子,其中剖分图是在原图的每条链路上放置一个顶点而得到的.当$H_{\text{original}}$描述一个拓扑系统时,在$H_{\text{root}}$的能谱中会出现非零能量的隙内边缘态,这是$H_{\text{original}}$中零能量拓扑边缘态的固有性质.在这种情况下,$H_{\text{root}}$描述平方根拓扑绝缘体或超导体。典型的例子是Su-Schrieffer-Heeger(SSH)模型的平方根,Kitaev拓扑超导体模型和Haldinger模型。我们的方案也适用于非厄米拓扑系统,在那里我们研究了一个非互易非厄米SSH模型的例子。

英文摘要:

We propose a general scheme to construct a Hamiltonian $H_{\text{root}}$ describing a square root of an original Hamiltonian $H_{\text{original}}$ based on the graph theory. The square-root Hamiltonian is defined on the subdivided graph of the original graph of $H_{\text{original}}$, where the subdivided graph is obtained by putting one vertex on each link in the original graph. When $H_{\text{original}}$ describes a topological system, there emerge in-gap edge states at non-zero energy in the spectrum of $H_{\text{root}}$, which are the inherence of the topological edge states at zero energy in $H_{\text{original}}$. In this case, $H_{\text{root}}$ describes a square-root topological insulator or superconductor. Typical examples are square roots of the Su-Schrieffer-Heeger (SSH) model, the Kitaev topological superconductor model and the Haldane model. Our scheme is also applicable to non-Hermitian topological systems, where we study an example of a nonreciprocal non-Hermitian SSH model.

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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