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arXiv 2102.05059cond-mat.mes-hall
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二维及更高维的普适非厄米趋肤效应

Universal non-Hermitian skin effect in two and higher dimensions

Kai Zhang, Zhesen Yang, Chen Fang

摘要:

集肤效应是在一维空间中实验发现的一种物理现象,它描述了在开链上,大量非厄米哈密顿量的本征态局域在链的末端。本文在二维及更高维空间中,建立了集肤效应存在的一个定理,当且仅当哈密顿量的边界谱覆盖复平面上的一个有限区域。这个定理建立了这个效应的普适性,因为几乎所有一般的非厄米哈密顿都满足上述条件,并且与一维不同,它与所有的空间对称性相容。我们提出了两种新类型的趋肤效应在两个和更高的维度:角落的趋肤效应,所有本征态都定位在一个角落的系统,和几何形状相关的趋肤效应,皮肤模式消失的系统的一个特定的形状,但出现在通用多边形。我们的定理的直接推论是,任何非厄米系统具有特殊的点(线)在两(三)维表现出趋肤效应,使这种现象可以在光子晶体,外尔半金属,近藤绝缘体的实验。

英文摘要:

Skin effect, experimentally discovered in one dimension, describes the physical phenomenon that on an open chain, an extensive number of eigenstates of a non-Hermitian hamiltonian are localized at the end(s) of the chain. Here in two and higher dimensions, we establish a theorem that the skin effect exists, if and only if periodic-boundary spectrum of the hamiltonian covers a finite area on the complex plane. This theorem establishes the universality of the effect, because the above condition is satisfied in almost every generic non-Hermitian hamiltonian, and, unlike in one dimension, is compatible with all spatial symmetries. We propose two new types of skin effect in two and higher dimensions: the corner-skin effect where all eigenstates are localized at one corner of the system, and the geometry-dependent-skin effect where skin modes disappear for systems of a particular shape, but appear on generic polygons. An immediate corollary of our theorem is that any non-Hermitian system having exceptional points (lines) in two (three) dimensions exhibits skin effect, making this phenomenon accessible to experiments in photonic crystals, Weyl semimetals, and Kondo insulators.

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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