Quantum Monte Carlo analysis of exchange and correlation in the strongly inhomogeneous electron gas - art. no. 036401

We use the variational quantum Monte Carlo method to calculate the density- functional exchange-correlation hole n(xc), the exchange-correlation energy density e(xc), and the total exchange-correlation energy E-xc of several s trongly inhomogeneous electron gas systems. We compare our results with the local density approximation and the generalized gradient approximation. It is found that the nonlocal contributions to e(xc) contain an energetically significant component, the magnitude, shape, and sign of which are control led by the Laplacian of the electron density.