  We consider a homogeneous 2D Bose gas with repulsive dipole-dipole
interactions. The ground-state equation of state, calculated using the
Diffusion Monte Carlo method, shows quantitative differences with predictions
of commonly used Gross-Pitaevskii mean-field theory. The static structure
factor, pair distribution function and condensate fraction are calculated in a
wide range of the gas parameter. Differences with mean-field theory are
reflected in the frequency of the lowest ``breathing'' mode for harmonically
trapped systems.
