Direction reversal of non-Hermitian skin effect via coherent coupling

TL;DR

This paper demonstrates that coherent coupling between non-Hermitian chains can reverse the direction of the non-Hermitian skin effect, with implications for controlling particle transport in quantum systems.

Contribution

It introduces a novel mechanism for reversing the non-Hermitian skin effect through coherent coupling, expanding understanding of eigenstate localization in non-Hermitian systems.

Findings

Direction reversal of NHSE observed in coupled non-Hermitian chains.

Time evolution dynamics analyzed using non-Hermitian quantum walk platform.

Potential applications in controlling transport phenomena in quantum systems.

Abstract

Absolute negative mobility (ANM) in nonequilibrium systems depicts the possibility of particles propagating toward the opposite direction of an external force. We uncover in this work a phenomenon analogous to ANM regarding eigenstate localization and particle transport in non-Hermitian systems under the influence of the non-Hermitian skin effect (NHSE). A coherent coupling between two non-Hermitian chains individually possessing the same preferred direction of NHSE is shown to cause a direction reversal of NHSE for all eigenmodes. This concept is further investigated in terms of time evolution dynamics using a non-Hermitian quantum walk platform within reach of current experiments. Our findings are explained both qualitatively and quantitatively. The possible direction reversal of NHSE can potentially lead to interesting applications.