Publications (36)
Study of the Shastry Sutherland Model Using Multi-scale Entanglement Renormalization Ansatz
Jie Lou, Takafumi Suzuki, Kenji Harada +1
We performed variational calculation based on the multi-scale entanglemnt renormalization ansatz, for the antiferromagnetic Heisenberg model on a Shastry Sutherland lattice (SSL).…
Dimer-Quadrupolar Quantum Phase Transition in the Quasi-One-Dimensional Heisenberg Model with Biquadratic Interaction
Kenji Harada, Naoki Kawashima, Matthias Troyer
The quasi-one-dimensional S=1 Heisenberg antiferromagnet with a biquadratic term is investigated at zero temperature by quantum Monte Carlo simulation. As the magnitude of the inte…
Universal Jump in the Helicity Modulus of the Two-Dimensional Quantum XY Model
Kenji Harada, Naoki Kawashima
The helicity modulus of the S=1/2 XY model is precisely estimated through a world line quantum Monte Carlo method enhanced by a cluster update algorithm. The obtained estimates for…
Plastic tensor networks for interpretable generative modeling
Katsuya O. Akamatsu, Kenji Harada, Tsuyoshi Okubo +1
A structural optimization scheme for a single-layer nonnegative adaptive tensor tree (NATT) that models a target probability distribution is proposed as an alternative paradigm for…
Quantum Circuit Simulation by SGEMM Emulation on Tensor Cores and Automatic Precision Selection
Hiroyuki Ootomo, Hidetaka Manabe, Kenji Harada +1
Quantum circuit simulation provides the foundation for the development of quantum algorithms and the verification of quantum supremacy. Among the various methods for quantum circui…
Néel and Spin-Peierls ground states of two-dimensional SU(N) quantum antiferromagnets
Kenji Harada, Naoki Kawashima, Matthias Troyer
The two-dimensional SU(N) quantum antiferromagnet, a generalization of the quantum Heisenberg model, is investigated by quantum Monte Carlo simulations. The ground state for $N\le…
Universal Information-Theoretic Structure of the Quasi-Stationary Domany--Kinzel Automaton
Hyun-Yong Lee, Kenji Harada, Naoki Kawashima
We characterize the quasi-stationary distribution (QSD) of the bond directed-percolation line of the Domany--Kinzel automaton using a matrix-product-state representation of the pro…
Tensor tree learns hidden relational structures in data to construct generative models
Kenji Harada, Tsuyoshi Okubo, Naoki Kawashima
Based on the tensor tree network with the Born machine framework, we propose a general method for constructing a generative model by expressing the target distribution function as…
Entropy Governed by the Absorbing State of Directed Percolation
Kenji Harada, Naoki Kawashima
We investigate the informational aspect of (1+1)-dimensional directed percolation, a canonical model of a nonequilibrium continuous transition to a phase dominated by a single spec…
Entanglement branching operator
Kenji Harada
We introduce an entanglement branching operator to split a composite entanglement flow in a tensor network which is a promising theoretical tool for many-body systems. We can optim…
Parallelized Quantum Monte Carlo Algorithm with Nonlocal Worm Updates
Akiko Masaki-Kato, Takafumi Suzuki, Kenji Harada +2
Based on the worm algorithm in the path-integral representation, we propose a general quantum Monte Carlo algorithm suitable for parallelizing on a distributed-memory computer by d…
Improving accuracy of tree-tensor network approach by optimization of network structure
Toshiya Hikihara, Hiroshi Ueda, Kouichi Okunishi +2
Numerical methods based on tensor networks have been extensively explored in the research of quantum many-body systems in recent years. It has been recognized that the ability of t…
Recent Developments of World-Line Monte Carlo Methods
Naoki Kawashima, Kenji Harada
World-line quantum Monte Carlo methods are reviewed with an emphasis on breakthroughs made in recent years. In particular, three algorithms -- the loop algorithm, the worm algorith…
Quantum critical dynamics in two-dimensional transverse Ising model
Chisa Hotta, Tempei Yoshida, Kenji Harada
In the vicinity of the quantum critical point(QCP), thermodynamic properties diverge toward zero temperature governed by universal exponents. Although this fact is well known, how…
Visualization of Entanglement Geometry by Structural Optimization of Tree Tensor Network
Toshiya Hikihara, Hiroshi Ueda, Kouichi Okunishi +2
In tensor-network analysis of quantum many-body systems, it is of crucial importance to employ a tensor network with a spatial structure suitable for representing the state of inte…
The Two-Dimensional S=1 Quantum Heisenberg Antiferromagnet at Finite Temperatures
Kenji Harada, Matthias Troyer, Naoki Kawashima
The temperature dependence of the correlation length, susceptibilities and the magnetic structure factor of the two-dimensional spin-1 square lattice quantum Heisenberg antiferroma…
Diffusion in the Continuous-Imaginary-Time Quantum World-Line Monte Carlo Simulations with Extended Ensembles
Kenji Harada, Yuto Kuge
The dynamics of samples in the continuous-imaginary-time quantum world-line Monte Carlo simulations with extended ensembles are investigated. In the case of a conventional flat ens…
Loop algorithm for Heisenberg models with biquadratic interaction and phase transitions in two dimensions
Kenji Harada, Naoki Kawashima
We present a new algorithm for quantum Monte Carlo simulation based on global updating with loops. While various theoretical predictions are confirmed in one dimension, we find, fo…
Short-time dynamics and magnetic critical behavior of two-dimensional random-bond Potts model
He-Ping Ying, Kenji Harada
The critical behavior in the short-time dynamics for the random-bond Potts ferromagnet in two-dimensions is investigated by short-time dynamic Monte Carlo simulations. The numerica…
Finite- scaling analysis of Berezinskii-Kosterlitz-Thouless phase transitions and entanglement spectrum for the six-state clock model
Hiroshi Ueda, Kouichi Okunishi, Kenji Harada +4
We investigate the Berezinskii-Kosterlitz-Thouless transitions for the square-lattice six-state clock model with the corner-transfer matrix renormalization group (CTMRG). Scaling a…
Numerical study of incommensurability of the spiral state on spin-1/2 spatially anisotropic triangular antiferromagnets using entanglement renormalization
Kenji Harada
The ground state of an S=1/2 antiferromagnetic Heisenberg model on a spatially anisotropic triangular lattice, which is an effective model of Mott insulators on a triangular layer…
A quantum Monte Carlo algorithm for softcore boson systems
Jurij Smakov, Kenji Harada, Naoki Kawashima
An efficient Quantum Monte Carlo algorithm for the simulation of bosonic systems on a lattice in a grand canonical ensemble is proposed. It is based on the mapping of bosonic model…
Kosterlitz-Thouless transition of quantum XY model in two dimensions
Kenji Harada, Naoki Kawashima
The two-dimensional XY model is investigated with an extensive quantum Monte Carlo simulation. The helicity modulus is precisely estimated through a continuous-time loop al…
Kernel method for corrections to scaling
Kenji Harada
Scaling analysis, in which one infers scaling exponents and a scaling function in a scaling law from given data, is a powerful tool for determining universal properties of critical…
Thermal Phase Transition of Generalized Heisenberg Models for SU(N) Spins on Square and Honeycomb Lattices
Takafumi Suzuki, Kenji Harada, Haruhiko Matsuo +2
We investigate thermal phase transitions to a valence-bond solid phase in SU(N) Heisenberg models with four- or six-body interactions on a square or honeycomb lattice, respectively…
Symmetry-protected topological order and negative-sign problem for SO(N) bilinear-biquadratic chains
Kouichi Okunishi, Kenji Harada
Using a generalized Jordan-Wigner transformation combined with the defining representation of the SO(N) spin, we map the SO(N) bilinear-biquadratic(BLBQ) spin chain into the N-colo…
SU(N) Heisenberg model with multi-column representations
Tsuyoshi Okubo, Kenji Harada, Jie Lou +1
The symmetric antiferromagnetic Heisenberg model with multi-column representations on the two-dimensional square lattice is investigated by quantum Monte Carlo sim…
Quantum World-line Monte Carlo Method with Non-binary Loops and Its Application
Kenji Harada
A quantum world-line Monte Carlo method for high-symmetrical quantum models is proposed. Firstly, based on a representation of a partition function using the Matsubara formula, the…
Automatic structural optimization of tree tensor networks
Toshiya Hikihara, Hiroshi Ueda, Kouichi Okunishi +2
Tree tensor network (TTN) provides an essential theoretical framework for the practical simulation of quantum many-body systems, where the network structure defined by the connecti…
Coarse-grained loop algorithms for Monte Carlo simulation of quantum spin systems
Kenji Harada, Naoki Kawashima
Recently, Syljuasen and Sandvik proposed a new framework for constructing algorithms of quantum Monte Carlo simulation. While it includes new classes of powerful algorithms, it is…
Quadrupolar Order in Isotropic Heisenberg Models with Biquadratic Interaction
Kenji Harada, Naoki Kawashima
Through Quantum Monte Carlo simulation, we study the biquadratic-interaction model with the SU(2) symmetry in two and three dimensions. The zero-temperature phase diagrams for the…
Universal spectrum structure at nonequilibrium critical points in the (1+1)-dimensional directed percolation
Kenji Harada
Using a tensor renormalization group method with oblique projectors for an anisotropic tensor network, we confirm that the rescaled spectrum of transfer matrices at nonequilibrium…
Neural Network Approach to Scaling Analysis of Critical Phenomena
Ryosuke Yoneda, Kenji Harada
Determining the universality class of a system exhibiting critical phenomena is one of the central problems in physics. There are several methods to determine this universality cla…
Possibility of Deconfined Criticality in SU(N) Heisenberg Models at Small N
Kenji Harada, Takafumi Suzuki, Tsuyoshi Okubo +5
To examine the validity of the scenario of the deconfined critical phenomena, we carry out a quantum Monte Carlo simulation for the SU() generalization of the Heisenberg model w…
Critical exponents in coupled phase-oscillator models on small-world networks
Ryosuke Yoneda, Kenji Harada, Yoshiyuki Y. Yamaguchi
A coupled phase-oscillator model consists of phase-oscillators, each of which has the natural frequency obeying a probability distribution and couples with other oscillators throug…
Bayesian Inference in the Scaling Analysis of Critical Phenomena
Kenji Harada
To determine the universality class of critical phenomena, we propose a method of statistical inference in the scaling analysis of critical phenomena. The method is based on Bayesi…