1.5k citations · 8.2k across the 35 of their papers we have counts for
35 papers
Universal hard-edge statistics of non-Hermitian random matrices
Zhenyu Xiao, Ryuichi Shindou, Kohei Kawabata
Random matrix theory is a powerful tool for understanding spectral correlations inherent in quantum chaotic systems. Despite diverse applications of non-Hermitian random matrix the…
Singular-Value Statistics of Non-Hermitian Random Matrices and Open Quantum Systems
Kohei Kawabata, Zhenyu Xiao, Tomi Ohtsuki +1
The spectral statistics of non-Hermitian random matrices are of importance as a diagnostic tool for chaotic behavior in open quantum systems. Here, we investigate the statistical p…
Lieb-Schultz-Mattis Theorem in Open Quantum Systems
Kohei Kawabata, Ramanjit Sohal, Shinsei Ryu
The Lieb-Schultz-Mattis (LSM) theorem provides a general constraint on quantum many-body systems and plays a significant role in the Haldane gap phenomena and topological phases of…
Hermitian Bulk -- Non-Hermitian Boundary Correspondence
Frank Schindler, Kaiyuan Gu, Biao Lian +1
Non-Hermitian band theory distinguishes between line gaps and point gaps. While point gaps can give rise to intrinsic non-Hermitian band topology without Hermitian counterparts, li…
Symmetry classification of typical quantum entanglement
Yuhan Liu, Jonah Kudler-Flam, Kohei Kawabata
Entanglement entropy of typical quantum states, also known as the Page curve, plays an important role in quantum many-body systems and quantum gravity. However, little has hitherto…
Non-Hermitian boost deformation
Taozhi Guo, Kohei Kawabata, Ryota Nakai +1
The Hatano-Nelson model is one of the most prototypical non-Hermitian models that exhibit the intrinsic non-Hermitian topological phases and the concomitant skin effect. These phen…
Symmetry of Open Quantum Systems: Classification of Dissipative Quantum Chaos
Kohei Kawabata, Anish Kulkarni, Jiachen Li +2
We develop a theory of symmetry in open quantum systems. Using the operator-state mapping, we characterize symmetry of Liouvillian superoperators for the open quantum dynamics by s…
Anisotropic Topological Anderson Transitions in Chiral Symmetry Classes
Zhenyu Xiao, Kohei Kawabata, Xunlong Luo +2
We study quantum phase transitions of three-dimensional disordered systems in the chiral classes (AIII and BDI) with and without weak topological indices. We show that the systems…
Dynamical quantum phase transitions in SYK Lindbladians
Kohei Kawabata, Anish Kulkarni, Jiachen Li +2
We study the open quantum dynamics of the Sachdev-Ye-Kitaev (SYK) model described by the Lindblad master equation, where the SYK model is coupled to Markovian reservoirs with jump…
Level statistics of real eigenvalues in non-Hermitian systems
Zhenyu Xiao, Kohei Kawabata, Xunlong Luo +2
Symmetries associated with complex conjugation and Hermitian conjugation, such as time-reversal symmetry and pseudo-Hermiticity, have great impact on eigenvalue spectra of non-Herm…
Entanglement Phase Transition Induced by the Non-Hermitian Skin Effect
Kohei Kawabata, Tokiro Numasawa, Shinsei Ryu
Recent years have seen remarkable development in open quantum systems effectively described by non-Hermitian Hamiltonians. A unique feature of non-Hermitian topological systems is…
Many-body topology of non-Hermitian systems
Kohei Kawabata, Ken Shiozaki, Shinsei Ryu
Non-Hermiticity gives rise to unique topological phases that have no counterparts in Hermitian systems. Such intrinsic non-Hermitian topological phases appear even in one dimension…
Nonlinear Landauer formula: Nonlinear response theory of disordered and topological materials
Kohei Kawabata, Masahito Ueda
The Landauer formula provides a general scattering formulation of electrical conduction. Despite its utility, it has been mainly applied to the linear-response regime, and a scatte…
Unifying the Anderson Transitions in Hermitian and Non-Hermitian Systems
Xunlong Luo, Zhenyu Xiao, Kohei Kawabata +2
Non-Hermiticity enriches the 10-fold Altland-Zirnbauer symmetry class into the 38-fold symmetry class, where critical behavior of the Anderson transitions (ATs) has been extensivel…
Topological Field Theory of Non-Hermitian Systems
Kohei Kawabata, Ken Shiozaki, Shinsei Ryu
Non-Hermiticity gives rise to unique topological phases without Hermitian analogs. However, the effective field theory has yet to be established. Here, we develop a field-theoretic…
Higher-order non-Hermitian skin effect
Kohei Kawabata, Masatoshi Sato, Ken Shiozaki
The non-Hermitian skin effect is a unique feature of non-Hermitian systems, in which an extensive number of boundary modes appear under the open boundary conditions. Here, we disco…
Nonunitary Scaling Theory of Non-Hermitian Localization
Kohei Kawabata, Shinsei Ryu
Non-Hermiticity can destroy Anderson localization and lead to delocalization even in one dimension. However, the unified understanding of the non-Hermitian delocalization has yet t…
Real spectra in non-Hermitian topological insulators
Kohei Kawabata, Masatoshi Sato
Spectra of bulk or edges in topological insulators are often made complex by non-Hermiticity. Here, we show that symmetry protection enables entirely real spectra for both bulk and…
Non-Bloch band theory of non-Hermitian Hamiltonians in the symplectic class
Kohei Kawabata, Nobuyuki Okuma, Masatoshi Sato
Non-Hermitian Hamiltonians are generally sensitive to boundary conditions, and their spectra and wave functions under open boundary conditions are not necessarily predicted by the…
Probing XY phase transitions in a Josephson junction array with tunable frustration
R. Cosmic, K. Kawabata, Y. Ashida +5
The seminal theoretical works of Berezinskii, Kosterlitz, and Thouless presented a new paradigm for phase transitions in condensed matter that are driven by topological excitations…
Continuous Phase Transition without Gap Closing in Non-Hermitian Quantum Many-Body Systems
Norifumi Matsumoto, Kohei Kawabata, Yuto Ashida +2
Contrary to the conventional wisdom in Hermitian systems, a continuous quantum phase transition between gapped phases is shown to occur without closing the energy gap in non-He…
Topological Classificaton of Non-Hermitian Gapless Phases: Exceptional Points and Bulk Fermi Arcs
Takumi Bessho, Kohei Kawabata, Masatoshi Sato
We provide classification of gapless phases in non-Hermitian systems according to two types of complex-energy gaps: point gap and line gap. We show that exceptional points, at whic…
Topological Origin of Non-Hermitian Skin Effects
Nobuyuki Okuma, Kohei Kawabata, Ken Shiozaki +1
A unique feature of non-Hermitian systems is the skin effect, which is the extreme sensitivity to the boundary conditions. Here, we reveal that the skin effect originates from intr…
Universality classes of non-Hermitian random matrices
Ryusuke Hamazaki, Kohei Kawabata, Naoto Kura +1
Non-Hermitian random matrices have been utilized in such diverse fields as dissipative and stochastic processes, mesoscopic physics, nuclear physics, and neural networks. However,…