384 citations · 1.9k across the 70 of their papers we have counts for
70 papers
Non-Hermitian skin effect enforced by nonsymmorphic symmetries
Yutaro Tanaka, Ryo Takahashi, Ryo Okugawa
Crystal symmetries play an essential role in band structures of non-Hermitian Hamiltonian. In this paper, we propose a non-Hermitian skin effect (NHSE) enforced by nonsymmorphic sy…
Bulk-edge correspondence of Stiefel-Whitney and Euler insulators through the entanglement spectrum and cutting procedure
Ryo Takahashi, Tomoki Ozawa
We propose an unconventional bulk-edge correspondence for two-dimensional Stiefel-Whitney insulators and Euler insulators, which are topological insulators protected by the sy…
Rotoinversion-symmetric bulk-hinge correspondence and its applications to higher-order Weyl semimetals
Yutaro Tanaka, Ryo Takahashi, Ryo Okugawa +1
We give a bulk-hinge correspondence for higher-order topological phases protected by rotoinversion symmetry in magnetic systems. Our approach allows us to show t…
Fractional hinge and corner charges in various crystal shapes with cubic symmetry
Katsuaki Naito, Ryo Takahashi, Haruki Watanabe +1
Higher-order topological insulators host gapless states on hinges or corners of three-dimensional crystals. Recent studies suggested that even topologically trivial insulators may…
Non-Hermitian band topology with generalized inversion symmetry
Ryo Okugawa, Ryo Takahashi, Kazuki Yokomizo
Non-Hermitian skin effects and exceptional points are topological phenomena characterized by integer winding numbers. In this study, we give methods to theoretically detect skin ef…
General corner charge formula in two-dimensional C_n-symmetric higher-order topological insulators
Ryo Takahashi, Tiantian Zhang, Shuichi Murakami
In this paper, we derive a general formula for the quantized fractional corner charge in two-dimensional C_n-symmetric higher-order topological insulators. We assume that the elect…