Universal conductance in the lowest Landau level

We have performed numerical calculations of the diagonal and off-diagonal (Hall) components of the conductivity tensor for a system of noninteracting electrons in two dimensions at high magnetic fields (lowest Landau level), in the presence of a random potential. We have considered five different potentials, with varying correlation length, with and without electron-hole symmetry. Our results are consistent, within statistical uncertainties, with a conductivity tensor at the critical energy with both components equal to 0.5e2/h. This suggests that the conductivity tensor at the lowest-Landau-level integer quantum Hall transition is universal, independent of the details for short-range random potentials.