Density functional theory and the von Weizsacker method

摘要: The response function of a uniform extended system noninteracting fermions, and thus the energy weakly perturbed this kind, is computed exactly in von Weizsacker approximation; it shown that (a) original coefficient leads to an upper bound which becomes asymptotically exact for short wavelength perturbations (b) reduced by factor 9 lower long waves. Generalisations these results are discussed case when fermions interacting electrons.