39 research outputs found
Dilute Spin Glass at Zero Temperature in General Dimension
We study the zero-temperature critical behavior of the dilute Ising spin glass. In our model nearest-neighbor exchange interactions randomly assume the values +J, 0, -J with probabilities p/2, 1-p, and p/2, respectively. We have generated 15th-order series for the Edwards-Anderson spin-glass susceptibility as a function of concentration p on hypercubic lattices in general dimension. Their analysis leads to critical concentrations and exponents that differ from those of percolation
Series Expansions for the Ising Spin Glass in General Dimension
We have developed 15th-order high-temperature series expansions for the study of the critical behavior of the Ising spin glass with nearest-neighbor exchange interactions each of which assumes the values ±J randomly. Series for the Edwards-Anderson spin-glass susceptibility (χEA) and two of its derivatives with respect to the ordering field have been evaluated for hypercubic lattices in general dimension, d. These extend previous general-dimension series by five terms. Certain measurable universal amplitude ratios have been estimated from the new series. Accurate critical data for d=5 and the first reliable estimates of the exponent β for d=4 and 5, are given. We quote γ=1.73±0.03, 2.00±0.25, and 2.7+1.0−0.6 and β=0.95±0.04, 0.9±0.1, and 0.7±0.2 in 5, 4, and 3 dimensions, respectively. Our results provide a smooth extrapolation between the mean-field results above six dimensions and experiments and simulations in physical dimensions. We relate our calculated derivatives of χEA to measurements of derivatives of the magnetization with respect to a uniform magnetic field
Phase Diagram of the Dilute Ising Spin Glass in General Spatial Dimension
We use high-temperature and low-concentration series to treat the dilute spin glass within a model with nearest-neighbor interactions which randomly assume the values +J, 0, -J with probabilities p/2, 1-p, p/2, respectively. Using the Harris no-free-end diagrams scheme in general spatial dimension, we obtained 15th-order series for χEA as a function of temperature for arbitrary dilution, 14th-order series for χEA as a function of dilution for selected temperatures, and 11th-order series for two higher derivatives of χEA with respect to the ordering field, where χEA is the Edwards-Anderson spin-glass susceptibility. Analysis of these series yields values of TSG(p), the critical temperature as a function of the dilution p or the analogous critical concentration pSG(T). Thus we determine a critical line, separating the spin-glass phase from the paramagnetic phase in the T-p plane. We find values of the critical exponent γ and universal amplitude ratios along the critical line. Universal amplitude ratios and dominant exponents along the critical line are identical to those of the pure spin glass for a wide range of dilution, indicating the same critical behavior as that of the pure spin glass