Ab-initio Electronic and Optical Properties of Low Dimensional Systems: from Single Particle to Many Body Approaches

Low dimensional systems, such as nanodots, nanotubes, nanowires, have attracted great interest in the last years, due to their possibleapplication in nanodevices. It is hence very important to describe accurately their electronic and optical properties within highly reliableand efficient ab-initio approaches. Density functional theory (DFT) has become in the last 20 years the standard technique for studyingthe ground-state properties, but this method often shows significant deviations from the experiment when electronic excited states areinvolved. The use of many-body Green’s functions theory, with DFT calculations taken as the zero order approximation, is todaythe state-of-the-art technique for obtaining quasi-particle excitation energies and optical spectra. In this paper we will present the currentstatus of this theoretical and computational approach, showing results for different kinds of low dimensional systems.