Ground-state properties of the three-dimensional Ising spin glass

We study zero-temperature properties of the three-dimensional Edwards-Anderson Ising spin glass on finite lattices up to size ${12}^3$. Using multicanonical sampling we generate large numbers of ground-state configurations in thermal equilibrium. Finite-size scaling fits of the data are carried out for two hypothetical scenarios: Parisi mean-field theory versus a droplet scaling ansatz. With a zero-temperature scaling exponent y=0.72±0.12 the data are well described by the droplet scaling ansatz. Alternatively, a description in terms of the Parisi mean-field behavior is still possible. The two scenarios give significantly different predictions on lattices of size ≥${12}^3$.