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arXiv 1807.08883quant-ph
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有限非Hermite系统例外点的经典对应

Classical correspondence of the exceptional points in the finite non-Hermitian system

X. Z. Zhang, G. Zhang, Z. Song

摘要:

系统地研究了有限非厄米特系统例外点的拓扑。基于Berry联系的具体形式,我们证明了本征态合并的例外线(EL)可以作为涡丝。EL的方向可以通过相应的Berry曲率来识别。在这种情况下,这种对应关系使EL的拓扑结构一目了然。作为一个例子,我们将这一发现应用到非厄米的Rice-Mele(RM)模型,其中的非厄米性来自交错的现场复势。边界EL是拓扑的,但非边界EL不是。每个非边界EL对应于两个临界动量,使相反的贡献贝里连接。因此,多粒子量子态的Berry联系可以具有经典对应,而经典对应仅由边界EL决定。此外,在参数空间中经历闭合路径的非零Berry相位取决于曲线如何围绕边界EL。这也提供了另一种方法来研究的拓扑结构的EP和它的物理对应在一个有限的非厄米特系统。

英文摘要:

We systematically study the topology of the exceptional point (EP) in the finite non-Hermitian system. Based on the concrete form of the Berry connection, we demonstrate that the exceptional line (EL), at which the eigenstates coalesce, can act as a vortex filament. The direction of the EL can be identified by the corresponding Berry curvature. In this context, such a correspondence makes the topology of the EL clear at a glance. As an example, we apply this finding to the non-Hermitian Rice-Mele (RM) model, the non-Hermiticity of which arises from the staggered on-site complex potential. The boundary ELs are topological, but the non-boundary ELs are not. Each non-boundary EL corresponds to two critical momenta that make opposite contributions to the Berry connection. Therefore, the Berry connection of the many-particle quantum state can have classical correspondence, which is determined merely by the boundary ELs. Furthermore, the non-zero Berry phase, which experiences a closed path in the parameter space, is dependent on how the curve surrounds the boundary EL. This also provides an alternative way to investigate the topology of the EP and its physical correspondence in a finite non-Hermitian system.

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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