In this work we have analyzed the following aspects of quantum complex syst
ems: I) Quantum-Classical correspondence for eigenfunctions (EFS) and local
density of states (LDOS) in dynamical chaotic models; 2) structure of LDOS
and EFS in matrix models with random two-body interaction; and 3) quantum
localization in ID correlated potentials. In I) we studied various models o
f two interacting particles and also a chaotic billiard. In 2), models of r
andomly interacting particles were used to analyze the nature of chaotic ei
genstates in isolated quantum systems of interacting particles. In 3) analy
tical, numerical, and experimental results are presented concerning the phe
nomenon of quantum localization in 1D correlated disordered potentials. We
discuss briefly the main results with an outline of the analytical and nume
rical approaches used to study these three aspects.