Enhancement of persistent current in a non-Hermitian disordered ring

TL;DR

This paper investigates how non-Hermiticity and disorder in a quasiperiodic ring enhance persistent currents, revealing new effects in both real and imaginary current components with potential implications for non-Hermitian physics.

Contribution

It demonstrates that non-Hermitian quasiperiodic disorder enhances persistent currents in a ring, including effects of Hubbard interactions, which is a novel insight into non-Hermitian disordered systems.

Findings

Persistent current increases with disorder strength and non-Hermiticity.

Both real and imaginary parts of the current are enhanced.

Hubbard interactions further boost the persistent current.

Abstract

We have studied the Aharonov-Bohm flux-induced magnetic response of a disordered non-Hermitian ring. The disorder is introduced through an on-site quasiperiodic potential described by the Aubry-Andr\'{e}-Harper (AAH) model, incorporating a complex phase that renders the model non-Hermitian. Our findings reveal that this form of non-Hermiticity enhances the persistent current, without requiring hopping dimerization. We explore both non-interacting and interacting scenarios. In the former, we examine spinless fermions, while in the latter, we consider fermions with Hubbard interactions. The Non-Hermitian phase induces both the real and imaginary components of the current. We thoroughly analyze the energy eigenspectrum, ground state energy, and persistent current in both real and imaginary spaces for various system parameters. Our primary goal is to investigate the combined effects of non-Hermiticity and disorder strength on persistent currents. We find an enhancement in both the real and imaginary components of the persistent current with increasing disorder strength, as well as the non-Hermiticity, up to a critical value. Furthermore, we observe an enhancement in persistent current in the presence of Hubbard correlation. Our findings may provide a new route to get nontrivial characteristics in persistent current for a special type of non-Hermitian systems.