Bulk-boundary correspondence in point-gap topological phases

Fuente: arXiv
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Hauptverfasser: Nakamura, Daichi, Bessho, Takumi, Sato, Masatoshi
Format: Preprint
Veröffentlicht: 2022
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author Nakamura, Daichi
Bessho, Takumi
Sato, Masatoshi
author_facet Nakamura, Daichi
Bessho, Takumi
Sato, Masatoshi
contents A striking feature of non-Hermitian systems is the presence of two different types of topology. One generalizes Hermitian topological phases, and the other is intrinsic to non-Hermitian systems, which are called line-gap topology and point-gap topology, respectively. Whereas the bulk-boundary correspondence is a fundamental principle in the former topology, its role in the latter has not been clear yet. This Letter establishes the bulk-boundary correspondence in the point-gap topology in non-Hermitian systems. After revealing the requirement for point-gap topology in the open boundary conditions, we clarify that the bulk point-gap topology in open boundary conditions can be different from that in periodic boundary conditions. On the basis of real space topological invariants and the $K$-theory, we give a complete classification of the open boundary point-gap topology with symmetry and show that the nontrivial open boundary topology results in robust and exotic surface states.
format Preprint
id arxiv_https___arxiv_org_abs_2205_15635
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Bulk-boundary correspondence in point-gap topological phases
Nakamura, Daichi
Bessho, Takumi
Sato, Masatoshi
Mesoscale and Nanoscale Physics
Mathematical Physics
Quantum Physics
A striking feature of non-Hermitian systems is the presence of two different types of topology. One generalizes Hermitian topological phases, and the other is intrinsic to non-Hermitian systems, which are called line-gap topology and point-gap topology, respectively. Whereas the bulk-boundary correspondence is a fundamental principle in the former topology, its role in the latter has not been clear yet. This Letter establishes the bulk-boundary correspondence in the point-gap topology in non-Hermitian systems. After revealing the requirement for point-gap topology in the open boundary conditions, we clarify that the bulk point-gap topology in open boundary conditions can be different from that in periodic boundary conditions. On the basis of real space topological invariants and the $K$-theory, we give a complete classification of the open boundary point-gap topology with symmetry and show that the nontrivial open boundary topology results in robust and exotic surface states.
title Bulk-boundary correspondence in point-gap topological phases
topic Mesoscale and Nanoscale Physics
Mathematical Physics
Quantum Physics
url https://arxiv.org/abs/2205.15635