4 citations · 7 across the 10 of their papers we have counts for
10 papers
Divergent Orbital Diamagnetism from Chiral Edge States in Chern Insulators
Nobuyuki Okuma
Two-dimensional massless Dirac systems, exemplified by graphene, are known to exhibit a divergent orbital diamagnetic susceptibility that scales linearly with system size. Motivate…
Predicting quantum ground-state energy by data-driven Koopman analysis of variational parameter nonlinear dynamics
Nobuyuki Okuma
In recent years, the application of machine learning to physics has been actively explored. In this paper, we study a method for estimating the ground-state energy of quantum Hamil…
Localized-basis formulation of interacting Hamiltonians in flat topological bands: coherent states and coherent-like states for fractional physics
Nobuyuki Okuma
In topological bands, it is impossible to construct exponentially localized Wannier functions while preserving the symmetries. Instead, in quantum Hall systems, one can define an o…
Steady-state skin effect in bosonic topological edge states under parametric driving
Nobuyuki Okuma
Non-Hermitian systems have attracted significant theoretical interest due to their extreme properties. However, realizations have mostly been limited to classical applications or a…
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…
Topological two-body interaction obstructing trivial ground states: an indicator of fractional Chern insulators
Nobuyuki Okuma, Tomonari Mizoguchi
The search for candidate materials for fractional Chern insulators (FCIs) has mainly focused on the topological and geometrical structures of single-particle Chern bands. However,…
Biorthogonal basis approach to fractional Chern physics
Nobuyuki Okuma
A fractional Chern insulator is thought to emerge from the competition between one-particle band topology and strong repulsive interactions. As an attempt to study lattice models o…
On equivalence of two formulas of orbital magnetic susceptibility for tight-binding models
Tomonari Mizoguchi, Nobuyuki Okuma
We prove that two formulas of the orbital magnetic susceptibility, namely, Koshino-Ando's formula and Gómez-Santos and Stauber's formula, are equivalent for the tight-binding model…
Constructing vortex functions and basis states of Chern insulators: ideal condition, inequality from index theorem, and coherent-like states on von Neumann lattice
Nobuyuki Okuma
In the field of fractional Chern insulators, a great deal of effort has been devoted to characterizing Chern bands that exhibit properties similar to the Landau levels. Among them,…
Bosonic Andreev bound state
Nobuyuki Okuma
A general free bosonic system with a pairing term is described by a bosonic Bogoliubov-de Gennes (BdG) Hamiltonian. The representation is given by a pseudo-Hermitian matrix, which…