Correlation Functions in the Fully Frustrated 2DXYModel

We present a detailed analysis of the critical properties of the two-dimensional XY model at full frustration. We calculate U(1) and Z₂ gauge-invariant correlation functions, as well as the chiral magnetization and susceptibility, by using extensive Monte Carlo simulations in lattices up to 240×{}240. The best fits to our results give νU(1)=0.3069, ηU(1)(TU(1)ᶜ=0.446)=0.1915, while ν_Z₂=0.875, 2β_Z₂=0.1936, 2γ_Z₂=1.82, 2γ_Z₂^'=1.025. These novel results are quantitatively different from those expected for separate 2D XY and 2D Ising models.