Non-Hermitian bidirectional robust transport

TL;DR

This paper demonstrates that in a quasi-one dimensional zigzag lattice with non-Hermitian hopping and a synthetic gauge field, robust bidirectional transport immune to backscattering can be achieved, extending non-Hermitian transport phenomena.

Contribution

It introduces a new model showing bidirectional non-Hermitian robust transport, unlike previous unidirectional cases, by using a zigzag lattice with imaginary hopping amplitudes.

Findings

Bidirectional robust transport observed in the zigzag lattice.

Transport remains immune to backscattering and disorder.

Extends non-Hermitian transport concepts to bidirectional regimes.

Abstract

Transport of quantum or classical waves in open systems is known to be strongly affected by non-Hermitian terms that arise from an effective description of system-enviroment interaction. A simple and paradigmatic example of non-Hermitian transport, originally introduced by Hatano and Nelson two decades ago [N. Hatano and D.R. Nelson, Phys. Rev. Lett. 77, 570 (1996)], is the hopping dynamics of a quantum particle on a one-dimensional tight-binding lattice in the presence of an imaginary vectorial potential. The imaginary gauge field can prevent Anderson localization via non-Hermitian delocalization, opening up a mobility region and realizing robust transport immune to disorder and backscattering. Like for robust transport of topologically-protected edge states in quantum Hall and topological insulator systems, non-Hermitian robust transport in the Hatano- Nelson model is unidirectional. However, there is not any physical impediment to observe robust bidirectional non-Hermitian transport. Here it is shown that in a quasi-one dimensional zigzag lattice, with non-Hermitian (imaginary) hopping amplitudes and a synthetic gauge field, robust transport immune to backscattering can occur bidirectionally along the lattice.