# Topological classification of non-Hermitian systems with reflection symmetry

## TL;DR

This paper classifies topological phases of non-Hermitian systems with reflection symmetry, revealing new invariants and bulk-edge correspondence in one-dimensional models, expanding the understanding of non-Hermitian topological matter.

## Contribution

It provides a comprehensive classification of non-Hermitian topological phases with reflection symmetry by mapping to Hermitian systems, introducing new invariants and analyzing bulk-edge correspondence.

## Key findings

- Classifies non-Hermitian topological phases with reflection symmetry.
- Identifies two types of topological invariants: winding numbers and Z2 numbers.
- Demonstrates bulk-edge correspondence for winding number characterized phases.

## Abstract

We classify topological phases of non-Hermitian systems in the Altland-Zirnbauer classes with an additional reflection symmetry in all dimensions. By mapping the non-Hermitian system into an enlarged Hermitian Hamiltonian with an enforced chiral symmetry, our topological classification is thus equivalent to classifying Hermitian systems with both chiral and reflection symmetries, which effectively change the classifying space and shift the periodical table of topological phases. According to our classification tables, we provide concrete examples for all topologically nontrivial non-Hermitian classes in one dimension and also give explicitly the topological invariant for each nontrivial example. Our results show that there exist two kinds of topological invariants composed of either winding numbers or $\mathbb{Z}_2$ numbers. By studying the corresponding lattice models under the open boundary condition, we unveil the existence of bulk-edge correspondence for the one-dimensional topological non-Hermitian systems characterized by winding numbers, however we did not observe the bulk-edge correspondence for the $\mathbb{Z}_2$ topological number in our studied $\mathbb{Z}_2$-type model.