My research activity can be roughly divided into two parts. On the one hand I deal with Conformal Perturbation Theory, namely a technique for studying systems in the vicinity of a critical point. The interesting aspect is that this kind of approach is very general and can be applied to different systems in different dimensions: some examples that I have dealt with are lattice gauge theories and the Ising model with a trapping potential. The other research line is dedicated to the study of holographic models to describe the transport properties of condensed matter systems, such as high-temperature superconductors, whose features are still to be fully investigated. The advantage of using these models is that it is easier to reach the strong coupling regime, an aspect that is usually hard to approach in "standard" field theories