5 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…
Non-Hermitian topological superconductivity with symmetry-enriched spectral and eigenstate features
Chuo-Kai Chang, Kazuma Saito, Nobuyuki Okuma +2
We investigate a one-dimensional superconducting lattice that realizes all internal symmetries permitted in non-Hermitian systems, characterized by nonreciprocal hopping, onsite di…
Quasi-two-dimensional spin helix and magnon-induced singularity in twisted bilayer graphene
Yung-Yeh Chang, Kazuma Saito, Chen-Hsuan Hsu
Twisted bilayer graphene exhibits prominent correlated phenomena in two distinct regimes: a Kondo lattice near the magic angle, resembling heavy fermion systems, and a triangular c…
Gapless superconductivity and its real-space topology in quasicrystals
Kazuma Saito, Masahiro Hori, Ryo Okugawa +2
We study superconductivity in Ammann-Beenker quasicrystals under magnetic field. By assuming an intrinsic -wave pairing interaction and solving for mean-field equations self-con…