Effetti di van der Waals a molti corpi nel modello degli oscillatori armonici quantistici. Applicazione a sistemi a bassa dimensionalità

In this work, we use the model of the quantum harmonic oscillators (QHOs), which allows to describe van der Waals interactions beyond the two-body approximation interaction, including many-body effects. After a theoretical introduction, the model is used to study a system consisting of a one-dimensional linear chain of carbon atoms; we analyze the energy spectrum of this system and the charge density fluctuations of its constituents, and we calculate the van der Waals interaction energy per atom. We also compute the pairwise interaction energy, in order to compare the two-body approach with the many-body one. It comes out that many-body effects are highly relevant for this low-dimensional system; they also bring evident deviations from low-order perturbative approaches.