The critical exponents of the two-dimensional Ising spin glass revisited: exact ground-state calculations and Monte Carlo simulations

The critical exponents for T → 0 of the two-dimensional Ising spin-glass model with Gaussian couplings are determined with the help of exact ground states for system sizes up to L = 50 and by a Monte Carlo study of a pseudo-ferromagnetic order parameter. We obtain: for the stiffness exponent y(= θ) = −0.281±0.002, for the magnetic exponent δ = 1.48±0.01 and for the chaos exponent ζ = 1.05 ± 0.05. From Monte Carlo simulations we get the thermal exponent ν = 3.6 ± 0.2. The scaling prediction y = −1/ν is fulfilled within the error bars, whereas there is a disagreement with the relation y = 1 − δ.