Exploring non-Hermitian phase transitions and reentrant localization in one-dimensional doubly-coupled lattices with asymmetric hopping
Phys. Rev. A 113, 013726 – Published 16 January, 2026
DOI: https://doi.org/10.1103/xcf6-f9bt
Abstract
Non-Hermitian effects and reentrant localization have attracted significant attention due to their unique physical properties and potential applications. Despite recent experimental advancements, achieving precise control and gaining a deeper theoretical understanding of these phenomena remain challenging. Here, we propose a one-dimensional doubly coupled lattice model, where two sublattices are interconnected via both horizontal and vertical hoppings, to investigate non-Hermitian phase transitions and localization behavior. Asymmetric hopping drives a transition from the Hermitian to the non-Hermitian regime, leading to the emergence of complex energy spectra. Moreover, when a quasiperiodic potential is introduced, the system exhibits a range of localization phases, including extended, localized, and intermediate phases characterized by mobility edges. Notably, under strong quasiperiodic modulation, we observe reentrant localization, where the system undergoes a nonmonotonic transition from localization to delocalization and back to localization as system parameters are varied. Our findings bridge theoretical insight into non-Hermitian phase transitions and localization with a practical circuit-based platform, enabling direct experimental exploration in quantum simulators.
