Critical conductance and its fluctuations at integer hall plateau transitions

Under periodic boundary conditions in the transverse direction, we calculate the averaged zero-temperature two-terminal conductance [G] and its statistical fluctuation [(delta G)(2n)], for n less than or equal to 4, at the critical point of integer quantum Hall plateau transitions. We find universal values for [G] = (0.58 +/- 0.03)e(2)/h, and [(delta G)(2n)] = (e(2)/h)(2n)A(2 pi), where A(2,4,6,8) = 0.081 +/- 0.005, 0.013 +/- 0.003, 0.0026 +/- 0.005, and (8 +/- 2) x 10(-4), respectively. We also determine the leading finite size scaling corrections to these observables, and make comparisons with experiments.