Topological phases protected by shifted sublattice symmetry in dissipative quantum systems

TL;DR

This paper introduces a new topological classification for dissipative quantum systems based on shifted sublattice symmetry, expanding the symmetry classes and demonstrating edge states protected by this symmetry.

Contribution

It unveils a novel topological classification of Lindbladians using shifted sublattice symmetry, increasing the known symmetry classes and confirming protected edge states in a dissipative model.

Findings

Shifted SLS can classify Lindbladians into more symmetry classes.

Edge states are protected by shifted SLS in the constructed model.

Presence of shifted SLS influences observable dynamics.

Abstract

Dissipative dynamics of quantum systems can be classified topologically based on the correspondence between the Lindbladian in the Gorini-Kossakowski-Sudarshan-Lindblad equation and the non-Hermitian Hamiltonian in the Schr\"{o}dinger equation. While general non-Hermitian Hamiltonians are classified into 38 symmetry classes, previous studies have shown that the Lindbladians are classified into 10 symmetry classes due to a physical constraint. In this work, however, we unveil a topological classification of Lindbladians based on shifted sublattice symmetry (SLS), which can increase the number of symmetry classes for the Lindbladians. We introduce shifted SLS so that the Lindbladian can retain this symmetry and take on the same role as SLS for the topological classification. For verification, we construct a model of a dissipative quantum system retaining shifted SLS and confirm the presence of edge states protected by shifted SLS. Moreover, the relationship between the presence of shifted SLS protected edge states and the dynamics of an observable quantity is also discussed.