Diffusion Monte Carlo study of circular quantum dots

We present ground- and excited-state energies obtained from diffusion Monte Carlo (DMC) calculations, using accurate multiconfiguration wave functions, for N electrons $(N<~13)$ confined to a circular quantum dot. We compare the density and correlation energies to the predictions of local spin density approximation (LSDA) theory and Hartree-Fock (HF) theory, and analyze the electron-electron pair-correlation functions. The DMC estimated change in electrochemical potential as a function of the number of electrons in the dot is compared to that from LSDA and HF calculations. Hund's first rule is found to be satisfied for all dots except $N=4$ for which there is a near degeneracy.