8 research outputs found
CAM Analysis of Dimensionality Crossover
Layered square-lattice ferromagnetic Ising models (∞×∞×n lattices) are studied by the Monte Carlo simulation for n=3 to 9. The results show the dimensionality crossover from the two-dimensional square lattice Ising model to the three-dimensional simple cubic Ising model. The shift exponent λ is estimated to be λ=1.64, which is consistent with the genral expectation that λ=1/ν_. Furthermore, CAM analysis is performed to evaluate the critical exponent γ of the three-dimensional simple cubic ferromagnetic Ising model, which shows that γ=1.21(4). The present analysis is also applicable to the study of the phase transition of quantum spin systems
A New Method to Calculate the Spin-Glass Order Parameter of the Two-Dimensional +/-J Ising Model
A new method to numerically calculate the th moment of the spin overlap of
the two-dimensional Ising model is developed using the identity derived
by one of the authors (HK) several years ago. By using the method, the th
moment of the spin overlap can be calculated as a simple average of the th
moment of the total spins with a modified bond probability distribution. The
values of the Binder parameter etc have been extensively calculated with the
linear size, , up to L=23. The accuracy of the calculations in the present
method is similar to that in the conventional transfer matrix method with about
bond samples. The simple scaling plots of the Binder parameter and the
spin-glass susceptibility indicate the existence of a finite-temperature
spin-glass phase transition. We find, however, that the estimation of is strongly affected by the corrections to scaling within the present data
(). Thus, there still remains the possibility that ,
contrary to the recent results which suggest the existence of a
finite-temperature spin-glass phase transition.Comment: 10 pages,8 figures: final version to appear in J. Phys.