Non-Hermitian phases and reentrant localization in a one-dimensional double chain with nonreciprocal coupling
Phys. Rev. A 113, 033721 – Published 13 March, 2026
DOI: https://doi.org/10.1103/ph7b-4pjj
Abstract
Non-Hermitian systems exhibit unique phenomena beyond conventional Hermitian physics, such as the non-Hermitian skin effect (NHSE) and exceptional points (EPs). In this work we introduce a one-dimensional double-chain model with nonreciprocal coupling to investigate the interplay between the NHSE and Anderson localization induced by quasiperiodic modulation. In the clean limit, the system exhibits a complex spectrum featuring EPs, tunable parity-time-symmetry breaking, and band splitting. When a quasiperiodic potential is added, a rich phase diagram emerges, including extended, localized, and critical phases, as well as mobility edges. Remarkably, we observe reentrant localization nonmonotonic transitions between extended and localized states driven by the competition between the NHSE and disorder scattering. Furthermore, we propose a concrete circuit implementation using negative-impedance converters, offering an experimentally accessible platform to simulate these non-Hermitian topological and localization effects at the classical level. Our results deepen the understanding of phase transitions in non-Hermitian quasicrystals and provide a direct route toward controllable simulators for observing and manipulating such phenomena in classical and future quantum settings.
