Tuning Topological States by Dissipation

TL;DR

This paper explores how the bulk-boundary correspondence in non-Hermitian topological systems breaks down when gradually tearing the system, revealing hybrid phase diagrams and multiple phase transitions through analytical and numerical methods.

Contribution

It demonstrates how tuning gain and loss domain walls causes a gradual breakdown of bulk-boundary correspondence, leading to hybrid phase diagrams in the thermodynamic limit.

Findings

Bulk-boundary correspondence breaks down gradually with gain/loss tuning.

Global phase diagrams become hybrids of periodic and open boundary conditions.

Multiple phase transitions occur during the breakdown process.

Abstract

The bulk-boundary correspondence plays a crucial role in topological quantum systems, however,this principle is broken in non-Hermitian systems. The breakdown of the bulk-boundary correspondence indicates that the global phase diagrams under open boundary conditions are significantly different from those under periodic boundary conditions. In this paper, we investigate how the bulk-boundary correspondence breaks down by gradually tearing the system. We find that by tuning the strength of gain and loss domain wall, in the thermodynamic limit, the global phase diagrams of the topological system become the hybrids of those under periodic and open boundary conditions. Moreover, during the breakdown of the bulk-boundary correspondence, several phase transitions occur. This situation is quite different from earlier work, where the breakdown of the bulk-boundary correspondence in the thermodynamic limit occurred suddenly due to infinitesimal boundary hopping amplitudes. To support our conclusions, we provide both analytical and numerical calculations. These results help researchers better understand non-Hermitian topological systems.