Topology and universality in the lattice CP2 model

The topological susceptibility χ_t and the correlation length ξ in the CP² model on a two-dimensional triangular lattice are calculated by the Monte Carlo simulation method. Using variant lattice actions, we verify the universality of the dimensionless quantity χ_tξ² ～- 0.09 in the scaling region, thus indicating the presence of physical topological effects in the scaling limit. As a by-product, we obtain a combinatorial formula for the topological charge.