PT-symmetric topological near-zero interface state

TL;DR

This paper investigates topological near-zero edge states in PT-symmetric photonic lattices, revealing conditions for their stability and phase transitions, with implications for topological lasers and quantum computing.

Contribution

It introduces a binary PT-symmetric lattice design that supports stable topological near-zero interface states with real eigenvalues despite unbroken PT symmetry.

Findings

Near-zero edge states can be spontaneously broken despite unbroken PT symmetry.

A binary lattice supports stable topological interface states with real eigenvalues.

The structure exhibits phase transition behavior similar to bulk states.

Abstract

Photonic systems with parity-time (PT) symmetry and topology are attracting considerable attentions. In this work, topological near-zero edge states are studied in PT-symmetric photonic lattice and the results indicate that the near-zero edge states can be broken spontaneously in spite of the unbroken PT symmetry. To achieve the stable topological near-zero mode, a binary lattice with carefully designed PT-symmetric is proposed. Further study shows such a structure supports a stable topological interface state experiences phase transition similar to the bulk states in infinite lattice and thus possess real-eigenvalues even with unbroken PT phase. Our study enriches the content of non-Hermitian topological physics and might have potential applications in the fields of topological lasing and quantum computation.