Zobrazeno 1 - 10
of 70
pro vyhledávání: '"Nakamura, Tota"'
Sine-square deformation (SSD) is a treatment proposed in quantum systems, which spatially modifies a Hamiltonian, gradually decreasing the local energy scale from the center of the system toward the edges by a sine-squared envelope function. It is kn
Externí odkaz:
http://arxiv.org/abs/2109.06463
Autor:
Nakamura, Tota
Publikováno v:
Sci Rep 10, 14201 (2020)
The magnetization process is a very important probe to study magnetic materials, particularly in search of spin-liquid states in quantum spin systems. Regrettably, however, progress of the theoretical analysis has been unsatisfactory, mostly because
Externí odkaz:
http://arxiv.org/abs/1902.02941
Autor:
Nakamura, Tota
Publikováno v:
Phys. Rev. E 99, 023301 (2019)
A spin-glass transition has been investigated for a long time but we have not yet reached a conclusion due to difficulties in the simulations. They are slow dynamics, strong finite-size effects, and sample-to-sample dependences. We clarified that the
Externí odkaz:
http://arxiv.org/abs/1809.02739
Autor:
Nakamura, Tota
Publikováno v:
Phys. Rev. E 93, 011301 (2016)
We propose a change of style for numerical estimations of physical quantities from measurements to inferences. We estimate the most probable quantities for all the parameter region simultaneously by using the raw data cooperatively. Estimations with
Externí odkaz:
http://arxiv.org/abs/1506.01823
Autor:
Nakamura, Tota, Shirakura, Takayuki
Publikováno v:
J. Phys. Soc. Jpn. 84, 013701 (2015)
Numerical studies in random systems are plagued with strong finite-size effects and boundary effects. We introduce a window-measurement method as a practical solution to these difficulties. We observe physical quantities only within a subsystem locat
Externí odkaz:
http://arxiv.org/abs/1404.7590
Autor:
Nakamura, Tota
Publikováno v:
Phys. Rev. B 82, 014427 (2010)
The finite-size scaling method in the equilibrium Monte Carlo(MC) simulations and the finite-time scaling method in the nonequilibrium-relaxation simulations are compromised. MC time data of various physical quantities are scaled by the MC time data
Externí odkaz:
http://arxiv.org/abs/1002.2817
Publikováno v:
Phys. Rev. E 79, 065701 (2009)
A quantum-thermal annealing method using a cluster-flip algorithm is studied in the two-dimensional spin-glass model. The temperature (T) and the transverse field (Gamma) are decreased simultaneously with the same rate along a linear path on the T-Ga
Externí odkaz:
http://arxiv.org/abs/0903.2206
Autor:
Nakamura, Tota
We have developed an efficient Monte Carlo algorithm, which accelerates slow Monte Carlo dynamics in quasi-one-dimensional Ising spin systems. The loop algorithm of the quantum Monte Carlo method is applied to the classical spin models with highly an
Externí odkaz:
http://arxiv.org/abs/0809.2969
Autor:
Nakamura, Tota, Nishiwaki, Yoichi
Publikováno v:
Phys. Rev. B 78, 104422 (2008)
Extensive Monte Carlo simulations are performed to analyze a recent neutron diffraction experiment on a distorted triangular lattice compound RbCoBr$_3$. We consider a spin-lattice model, where both spin and lattice are Ising variables. This model ex
Externí odkaz:
http://arxiv.org/abs/0803.1710
Autor:
Nakamura, Tota
Dynamic scaling analyses are performed in the spin-glass phase of the $\pm J$ Ising, the {\it XY}, and the Heisenberg models in three dimensions. We found a crossover from the critical dynamics to the ground-state dynamics in the Ising model and the
Externí odkaz:
http://arxiv.org/abs/cond-mat/0606181