FAR-INFRARED RESPONSE OF QUANTUM DOTS - FROM FEW ELECTRON EXCITATIONSTO MAGNETOPLASMONS

We study the far-infrared (FIR) response of quantum dots with a variab le number N(s) of electrons and a non-parabolic confinement in a magne tic field B. For few electrons we compare the results of a Hartree (H) and a Hartree-Fock (HF) approach with those obtained by an exact diag onalization of the few-particle Hamiltonian. A good qualitative agreem ent is found between the HF approximation and the exact calculation. T he resonance spectra are fingerprints of the ground state of the elect ron system and depend therefore strongly on N(s) and B. With an increa sing number of electrons, the H- and the HF-calculations show new feat ures evolving in the FIR spectra. These features resemble the non-loca l mode coupling effects observed in the magnetoplasmon dispersion of t wo- and one-dimensional systems marking the transition to a quasi-clas sical hydrodynamic behaviour.