4 papers
Quasiperiodicity-induced non-Hermitian skin effect from the breakdown of scale-free localization
Kazuma Saito, Ryo Okugawa, Kazuki Yokomizo +2
Non-reciprocal systems exhibit extreme sensitivity to boundary conditions, typically manifesting as the non-Hermitian skin effect (NHSE) under open boundaries. By bridging the boun…
Quantum-geometric origin of superfluid weight in quasicrystals with critical states
Kazuma Saito, Ryo Okugawa, Yusuke Kato +1
A distinctive feature of many quasiperiodic systems is the presence of critical states that are neither extended nor exponentially localized. We investigate the geometric effect on…
Quasiperiodicity-induced bulk localization with self similarity in non-Hermitian systems
Yu-Peng Wang, Chuo-Kai Chang, Ryo Okugawa +1
We analyze the localization behavior in a non-Hermitian system subject to a quasiperiodic onsite potential. We characterize localization transitions using multiple quantitative ind…
Exceptional second-order topological insulators
Yutaro Tanaka, Daichi Nakamura, Ryo Okugawa +1
Point-gap topological phases of non-Hermitian systems exhibit exotic boundary states that have no counterparts in Hermitian systems. Here, we develop classification of second-order…