Two-dimensional electron gas: correlation energy versus density and spin polarization

We propose a simple analytic representation of the correlation energy for the two-dimensional electron gas, as a function of the density and the spin polarization. This new parametrization includes most of the known high- and low- density limits and fits our new fixed-node diffusion Monte Carlo simulations, performed for a wide range of electron densities and spin-polarization states. In this way we provide a reliable local-spin-density energy functional for two-dimensional systems. The corresponding correlation potential is discussed and compared with previous models.