Motivated by recent experiments on the conductance fluctuations in mesoscopic
integr quantum Hall systems, we consider a model in which the Coulomb
interactions are incorporated into the picture of edge-state transport through
a single saddle-point. The occupancies of `classical' localised states in the
two-dimensional electron system change due to the interactions between
electrons when the gate voltage on top of the device is varied. The
electrostatic potential between the localised states and the saddle-point
causes fluctuations of the saddle-point potential and thus fluctuations of the
transmission probability of edge states. This simple model is studied
numerically and compared with the observation.Comment: 6 pages with 3 figures. To be published in Physical Review