Quantum Monte Carlo study of the ground state of the two-dimensional Fermi fluid

We have used the variational and diffusion quantum Monte Carlo methods to calculate the energy, paircorrelation function, static structure factor, and momentum density of the ground state of the two-dimensional 2D homogeneous electron gas. We have used highly accurate Slater-Jastrow-backflow trial wave functions and twist averaging to reduce finite-size effects where applicable. We compare our results with others in the literature and construct a local-density-approximation exchange-correlation functional for 2D systems.