CORRELATION-FUNCTIONS IN THE FULLY FRUSTRATED 2D XY MODEL

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 x 240. The best fits to our results give nu(U)(1) = 0.3069, eta(U)(1)(T(U)(1)c = 0.446) = 0.1915, while nu(Z)2 = 0.875, 2-beta(Z)2, = 0.1936, 2-gamma(Z)2 = 1.82, 2-gamma(Z)2' = 1.025. These novel results are quantitatively different from those expected for separate 2D XY and 2D Ising models.