Novel localization phenomena and self-similarity in non-Hermitian quasiperiodic systems
Quasiperiodicity is known to induce localization and self-similarity in physical systems; however, previous research has predominantly focused on Hermitian systems. Extending this paradigm to the non-Hermitian regime, Dr. Chen-Hsuan Hsu’s team at the Institute of Physics now predict the emergence of qualitatively new localization phenomena in non-Hermitian quasiperiodic lattices. As the quasiperiodic potential strength increases, the eigenstates do not localize simultaneously. Instead, localization occurs sequentially, giving rise to step- or plateau-like structures as a function of the potential strength. Remarkably, these plateaus exhibit self-similarity: upon rescaling and increasing the resolution, the same step patterns reappear across scales. This work uncovers a new form of quasiperiodicity-induced localization unique to non-Hermitian systems. This research is in collaboration with Prof. Ryo Okugawa at Tokyo University of Science and has been published in Physical Review Research.
Reference:
Yu-Peng Wang, Chuo-Kai Chang, Ryo Okugawa, and Chen-Hsuan Hsu, Quasiperiodicity-induced bulk localization with self-similarity in non-Hermitian systems, Phys. Rev. Research 7, 043353 (2025).
Journal Links: https://journals.aps.org/prresearch/abstract/10.1103/8txw-m2cp