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arXiv · 1905.02211

Non-Hermitian Topological Invariants in Real Space

Fei Song·Shunyu Yao·Zhong Wang
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Abstract

The topology of non-Hermitian systems is drastically shaped by the non-Hermitian skin effect, which leads to the generalized bulk-boundary correspondence and non-Bloch band theory. The essential part in formulations of bulk-boundary correspondence is a general and computable definition of topological invariants. In this paper, we introduce a construction of non-Hermitian topological invariants based directly on real-space wavefunctions, which provides a general and straightforward approach for determining non-Hermitian topology. As an illustration, we apply this formulation to several representative models of non-Hermitian systems, efficiently obtaining their topological invariants in the presence of non-Hermitian skin effect. Our formulation also provides a dual picture of the non-Bloch band theory based on the generalized Brillouin zone, offering a unique perspective of bulk-boundary correspondence.

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Fei Song, Shunyu Yao, Zhong Wang. 2019-12-10. Non-Hermitian Topological Invariants in Real Space. https://doi.org/10.1103/physrevlett.123.246801

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