FIXED-POINT ACTION AND TOPOLOGY IN THE CP3 MODEL

We define a fixed point action in two-dimensional lattice CPN-1 models . The fixed point action is a classical perfect lattice action, which is expected to show strongly reduced cutoff effects in numerical simul ations. Furthermore, the action has scale-invariant instanton solution s, which enables us to define a correct topological charge without top ological defects. Using a parametrization of the fixed point action fo r the CP3 model in a Monte Carlo simulation, we study the topological susceptibility.