Hidden-symmetry-protected topological phases on a one-dimensional lattice

TL;DR

This paper uncovers a new topological phase in a one-dimensional fermionic lattice with synthetic gauge fields, protected by hidden symmetries, expanding the understanding of topological insulators beyond standard classifications.

Contribution

It identifies a novel topological phase protected by hidden symmetries in a 1D lattice system, beyond the conventional Altland-Zirnbauer classification.

Findings

Existence of a topological phase with zero-mode edge states

Presence of a quantized Berry phase in the system

Hidden symmetries protect the topological phase

Abstract

We demonstrate the existence of topologically nontrivial phase in a one-dimensional fermionic lattice system subjected to synthetic gauge fields, which is beyond the standard Altland-Zirnbauer classification of topological insulators. The topological phase can be characterized by the presence of degenerate zero-mode edge states or a quantized Berry phase of the occupied Bloch band. By analyzing symmetries of the system, we identify that the topological phase and zero-mode edge states are protected by two hidden symmetries. An extended model with hidden symmetry breaking is also studied in order to reveal the effect of hidden symmetries on the symmetry protected topological phase.