Spin- and charge-density excitations in quantum dots via Quantum Monte Carlo simulation

The calculation of the polarizability provides a method of calculating the collective-modes excitation energies of an electronic system. However, the polarizability is a correlated quantity, thus demanding a major effort when Monte Carlo methods are used for its evaluation. Nevertheless, Quantum Monte Carlo results represent the benchmark in most many-body physics. We applied a correlated Variational and Diffusion Monte Carlo scheme to a GaAs-AlGaAs quantum dot. Comparison with Raman scattering experiments and previous calculations is considerable. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.