169 citations · 695 across the 25 of their papers we have counts for
25 papers
Matrix Product Renormalization Group: Potential Universal Quantum Many-Body Solver
Masahiko G. Yamada, Takumi Sanno, Masahiro O. Takahashi +4
The density matrix renormalization group (DMRG) is a celebrated tensor network algorithm, which computes the ground states of one-dimensional quantum many-body systems very efficie…
Semi-classical simulation of spin-1 magnets
Kimberly Remund, Rico Pohle, Yutaka Akagi +2
Theoretical studies of magnets have traditionally concentrated on either classical spins, or the extreme quantum limit of spin-1/2. However, magnets built of spin-1 moments are als…
Photocontrol of spin scalar chirality in centrosymmetric itinerant magnets
Atsushi Ono, Yutaka Akagi
Noncoplanar magnetic structures, such as magnetic skyrmions, are characterized by spin chirality and usually favored by antisymmetric exchange interactions in noncentrosymmetric ma…
Nonlinear magnon spin Nernst effect in antiferromagnets and strain-tunable pure spin current
Hiroki Kondo, Yutaka Akagi
In this Letter, we study the spin Nernst effect (SNE) of magnons in the nonlinear response regime. We derive the formula for the nonlinear magnon spin Nernst current by solving the…
Symmetry-protected quantization of complex Berry phases in non-Hermitian many-body systems
Shoichi Tsubota, Hong Yang, Yutaka Akagi +1
We investigate the quantization of the complex-valued Berry phases in non-Hermitian quantum systems with certain generalized symmetries. In Hermitian quantum systems, the real-valu…
Fractional Skyrmion molecules in a model
Yutaka Akagi, Yuki Amari, Sven Bjarke Gudnason +2
We study fractional Skyrmions in a baby Skyrme model with a generalization of the easy-plane potential. By numerical methods, we find stable, metastable, and unstab…
Isolated Skyrmions in the nonlinear -model with a Dzyaloshinskii-Moriya type interaction
Yutaka Akagi, Yuki Amari, Nobuyuki Sawado +1
We study two dimensional soliton solutions in the nonlinear -model with a Dzyaloshinskii-Moriya type interaction. First, we derive such a model as a continuous limit of t…
Dirac surface states in magnonic analogs of topological crystalline insulators
Hiroki Kondo, Yutaka Akagi
We propose magnonic analogs of topological crystalline insulators which possess Dirac surface states protected by the combined symmetry of time-reversal and half translation. Const…
Topological Invariant for Bosonic Bogoliubov-de Gennes Systems with Disorder
Yutaka Akagi
Using the method of noncommutative geometry, we define a topological invariant in disordered bosonic Bogoliubov-de Gennes systems, which possess a unique mathematical property---no…
Non-Hermiticity and topological invariants of magnon Bogoliubov-de Gennes systems
Hiroki Kondo, Yutaka Akagi, Hosho Katsura
Since the theoretical prediction and experimental observation of the thermal Hall effect of magnons, a variety of novel phenomena that may occur in magnonic systems have been propo…
Three-dimensional topological magnon systems
Hiroki Kondo, Yutaka Akagi, Hosho Katsura
We propose a class of models for a magnonic analog of topological insulators in three dimensions. The models have pseudo-time-reversal symmetry which ensures the existence of boson…
Transforming Generalized Ising Model into Boltzmann Machine
Nobuyuki Yoshioka, Yutaka Akagi, Hosho Katsura
We find an exact mapping from the generalized Ising models with many-spin interactions to equivalent Boltzmann machines, i.e., the models with only two-spin interactions between ph…
Topological Invariant for Magnon Spin Hall Systems
Hiroki Kondo, Yutaka Akagi, Hosho Katsura
We propose a definition of a topological invariant for magnon spin Hall systems which are the bosonic analog of two-dimensional topological insulators in class AII.…
A New Numerical Method for Topological Insulators with Strong Disorder
Yutaka Akagi, Hosho Katsura, Tohru Koma
We propose a new method to numerically compute the indices for disordered topological insulators in Kitaev's periodic table. All of the indices are kn…
Learning Disordered Topological Phases by Statistical Recovery of Symmetry
Nobuyuki Yoshioka, Yutaka Akagi, Hosho Katsura
In this letter, we apply the artificial neural network in a supervised manner to map out the quantum phase diagram of disordered topological superconductor in class DIII. Given the…
Quantum solitons with emergent interactions in a model of cold atoms on the triangular lattice
Hiroaki T. Ueda, Yutaka Akagi, Nic Shannon
Cold atoms bring new opportunities to study quantum magnetism, and in particular, to simulate quantum magnets with symmetry greater than . Here we explore the topological ex…
Spontaneous formation of kagome network and Dirac half-semimetal on a triangular lattice
Yutaka Akagi, Yukitoshi Motome
In spin-charge coupled systems, geometrical frustration of underlying lattice structures can give rise to nontrivial magnetic orders and electronic states. Here we explore such a p…
Surface and interface effects on a magnetic Chern insulator
Ryo Ozawa, Masafumi Udagawa, Yutaka Akagi +1
Effects of an open surface on a magnetic Chern insulator are investigated in comparison with those of an interface to a capping magnetic layer. In magnets, an open surface often pe…
Reconstruction of chiral edge states in a magnetic Chern insulator
Ryo Ozawa, Masafumi Udagawa, Yutaka Akagi +1
We study reconstruction of the chiral edge states in a magnetic Chern insulator in the Kondo lattice model on a triangular lattice at 1/4 filling. In this state, the spin scalar ch…
Effect of Quantum Spin Fluctuation on Scalar Chiral Ordering in the Kondo Lattice Model on a Triangular Lattice
Yutaka Akagi, Masafumi Udagawa, Yukitoshi Motome
Spin scalar chiral ordering gives rise to nontrivial topological characters and peculiar transport properties. We here examine how quantum spin fluctuations affect the spin scalar…
Linear Spin Wave Analysis for General Magnetic Orders in the Kondo Lattice Model
Yutaka Akagi, Masafumi Udagawa, Yukitoshi Motome
We extend the formulation of the spin wave theory for the Kondo lattice model, which was mainly used for the ferromagnetic metallic state, to general magnetic orders including comp…
Ground-state phase diagram of the Kondo lattice model on triangular-to-kagome lattices
Yutaka Akagi, Yukitoshi Motome
We investigate the ground-state phase diagram of the Kondo lattice model with classical localized spins on triangular-to-kagome lattices by using a variational calculation. We iden…
Hidden Multiple-spin Interactions as an Origin of Spin Scalar Chiral Order in Frustrated Kondo Lattice Models
Yutaka Akagi, Masafumi Udagawa, Yukitoshi Motome
We reveal the significance of kinetic-driven multiple-spin interactions hidden in geometrically-frustrated Kondo lattice models. Carefully examining the perturbation in terms of th…
Noncoplanar spin canting in lightly-doped ferromagnetic Kondo lattice model on a triangular lattice
Yutaka Akagi, Yukitoshi Motome
Effect of the coupling to mobile carriers on the 120 antiferromagnetic state is investigated in a ferromagnetic Kondo lattice model on a frustrated triangular lattice. Usin…