  A $\theta$ term, which couples to topological charge, is added to the
two-dimensional lattice CP^3 model and U(1) gauge theory. Monte Carlo
simulations are performed and compared to strong-coupling character expansions.
In certain instances, a flattening behavior occurs in the free-energy at
sufficiently large $\theta$, but the effect is an artifact of the simulation
methods.

High Energy Physics - Lattice;High Energy Physics - Phenomenology