Anderson localization induced by complex potential

TL;DR

This paper explores how non-Hermitian complex potentials, including disorder and quasiperiodic types, induce Anderson localization and phase transitions in one-dimensional lattices, revealing interference patterns at transition points.

Contribution

It demonstrates that complex non-Hermitian potentials can induce localization and phase transitions similar to real potentials, with new insights into the role of imaginary quasiperiodic potentials.

Findings

Imaginary disorder induces Anderson localization in non-Hermitian SSH chains.

The non-Hermitian Aubry-Andre model exhibits a localization-delocalization transition.

Complex quasiperiodic potentials show interference patterns at transition points.

Abstract

Uncorrelated disorder potential in one-dimensional lattice definitely induces Anderson localization, while quasiperiodic potential can lead to both localized and extended phases, depending on the potential strength. We investigate the Anderson localization in one-dimensional lattice with nonHermitian complex disorder and quasiperiodic potential. We present a non-Hermitian SSH chain to demonstrate that a nonzero imaginary disorder on-site potential can induce the standard Anderson localization. We also show that the non-Hermitian Aubry-Andre (AA) model exhibits a transition in parameter space, which separates the localization and delocalization phases and is determined by the self-duality of the model. It indicates that a pure imaginary quasiperiodic potential takes the same role as a real quasiperiodic potential in the transition point between localization and delocalization. Remarkably, a system with complex quasiperiodic potential exhibits interference-like pattern on the transition points.