Density-functional theory of spin-polarized disordered quantum dots - art.no. 075301

Using density-functional theory, we investigate fluctuations of the ground- state energy of spin-polarized, disordered quantum dots in the metallic reg ime. To compare to experiment, we evaluate the distribution of addition ene rgies and find a convolution of the Wigner-Dyson distribution, expected for noninteracting electrons, with a narrower Gaussian distribution. The width of the Gaussian is accurately given by the fluctuations in the screened Co ulomb interaction between a pair of electrons at the Fermi energy.