Research

My research work is in general in the field of nonequilibrium statistical physics and theory of complex systems. More in detail, I currently focus on the following topics:

• • Regularities and universality in large-scale social phenomena

  • Statistical physics approach to social dynamics

  • Nonequilibrium dynamics on complex topologies

Regularities and universality in large-scale social phenomena

In social phenomena every individual interacts with a limited number of peers, usually negligible as compared with the total number of people in the system. In spite of that, human societies are characterized by stunning global regularities. There are transitions from disorder to order, like the spontaneous emergence of a common language/culture or the creation of consensus about a specific topic. There are examples of scaling, as in the distribution of votes in elections. In order to understand the nature and the origin of such regularities it is crucial to characterize them in a quantitatively precise way, looking in particular for features that are universal, i.e. shared by different phenomena. The identification of such features is fundamental for devising sensible simple models able to reproduce the empirical observations and suitable for theoretical investigation.

Statistical physics approach to social dynamics

In recent years it has become widely recognized that many large-scale phenomena observed in social systems are the "macroscopic" complex effect of the "microscopic" simple behavior of a large number of interacting agents. This has led social scientists to the introduction of elementary models of social behavior (cellular automata, agent-based models). Many of these models are somehow relatives of models that have been introduced in modern traditional statistical physics, and it is natural to approach them using the same concepts and tools that have been successfully applied in physics.

Nonequilibrium dynamics on complex topologies

Dynamical processes have been studied for decades on regular lattices and their behavior is generally very well understood. When such processes take place on a complex network, what is the effect of the disordered interaction pattern on their phenomenology? In recent years I have been in particular involved in the investigation of the effect of the absence of a characteristic scale in scale-free networks on the behavior of the contact process. Interesting questions concern the validity of mean-field theory and the application of finite-size scaling theory.

Other research interests

I have interest in many other topics, including:

• • Community structure of complex networks

  • Non equilibrium surface growth

  • Instabilities and pattern formation in epitaxial growth

  • Phase-ordering dynamics