39 research outputs found

    Dilute Spin Glass at Zero Temperature in General Dimension

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    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

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    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

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    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

    Extremism and Social Learning

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    A Bargaining Power Theory of Gap-Filling

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    Beyond Judicial Minimalism

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