Ground states in three-dimensional +/- J Edwards-Anderson spin glasses with free boundaries

By an exact calculation of the ground states for the +/-J Edwards-Anderson spin glass, one can extrapolate the ground state energy to infinite system sizes. We calculate the exact ground states for the three-dimensional spin glass with free boundaries for system sizes up to 10 and fit different fini te-size functions. We cannot decide, only from the quality of the fit, whic h fitting function to choose. Relying on the literature values for the extr apolated energy, we find the finite-size corrections to vary as 1/L.