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arXiv · 2105.12913

Correlation effects on non-Hermitian point-gap topology in zero dimension: reduction of topological classification

Tsuneya Yoshida·Yasuhiro Hatsugai
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Abstract

We analyze a zero-dimensional correlated system with special emphasis on the non-Hermitian point-gap topology protected by chiral symmetry. Our analysis elucidates that correlations destroy an exceptional point on a topological transition point which separates two topological phases in the non-interacting case; one of them is characterized by the zero-th Chern number $N_{0\mathrm{Ch}}=0$, and the other is characterized by $N_{0\mathrm{Ch}}=2$. This fact implies that correlations allow to continuously connect the two distinct topological phases in the non-interacting case without closing the point-gap, which is analogous to the reduction of topological classifications by correlations in Hermitian systems. Furthermore, we also discover a Mott exceptional point, an exceptional point where only spin degrees of freedom are involved.

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Tsuneya Yoshida, Yasuhiro Hatsugai. 2021-05-27. Correlation effects on non-Hermitian point-gap topology in zero dimension: reduction of topological classification. https://doi.org/10.1103/physrevb.104.075106

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