Logarithmic corrections to scaling near the metal-insulator transition

It is shown that, for certain universality classes, logarithmic corrections to scaling and to some asymptotic power laws exist near the metal-insulator transition. These slow transients make it virtually impossible to experimentally probe the asymptotic critical reigon. Upon application of a magnetic field the transients are predicted to vanish, making the asymptotic region accessible. It is shown that, with the slow transients taken into account, the measured critical behavior of the conductivity in Si:P is consistent with a rigorous lower bound on the correlation length exponent.