Integer quantum Hall effect of interacting electrons: Dynamical sealing and critical conductivity

We report on a study of interaction effects on the polarization of a disord ered two-dimensional electron system in a strong magnetic held. Treating th e Coulomb interaction within the time-dependent Hartree-Fock approximation, we find numerical evidence for dynamical scaling with a dynamical critical exponent z = 1 at the integer quantum Hall plateau transition in the lowes t Landau level. Within the numerical accuracy of our data the conductivity at the transition and the anomalous diffusion exponent are given by the val ues for noninteracting electrons, independent of the strength of the intera ction.