Fluctuations in layered complex networks

Layered networks represent a natural extension of the successful complex network theory. They aim to model additional structure in the coupling and to account for

interdependent systems such as functional brain networks or coupled voltage levels in electric power grids. The latter are typically subjected to external perturbations or a

noisy environment, which, on the long run might damage some of the system components or, in extreme cases, drive the system through transitions between different fixed

point. Therefore, it is of primal importance to understand how perturbations spread over such layered networks. With this task in mind, I investigate how noise injected in one

layer is transmitted to its dependent layers. Interestingly, I show that, for networks with low algebraic connectivity, fluctuations might be strongly amplified while going from one layer to another, eventually leading to major system failures.