Integer quantum Hall effect of interacting electrons: dynamical scaling and critical conductivity

We report on a study of interaction effects on the polarization of a disordered two-dimensional electron system in a strong magnetic field. Treating the 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 lowest Landau level. Within the numerical accuracy of our data the conductivity at the transition and the anomalous diffusion exponent are given by the values for non-interacting electrons, independent of the strength of the interaction.