Momentum-space Monte Carlo

Using the quenched, reduced form of large-N field theories, we show that it is possible to directly measure momentum-space Green functions, via Monte Carlo, without going through the intermediate step of measurement in position space plus Fourier transformation. This promises to be useful tool for investigating the infrared structure of planar field theories. As an application (and test) of the method, we compute mass-gaps in the quenched U(N) × U(N) lattice chiral model, in D = 1 and 2 dimensions.