My activity inside Cactus Group, which is a group involved in reasearches about Complex Systems at the Department of Physics and Astronomy of Catania University, is mainly directed to the study of dynamics and thermodynamics of the so called Hamiltonian mean-field model (HMF). It is a model of planar rotators (XY) with long range interactions, exactly solvable in canonical ensemble and showing a second order equilibrium phase transition. In this respect it is paradigmatic of a large class of non-extensive systems, such as self-gravitating systems, multifragmented nuclear systems, atomic clusters, etc.

With my colleagues of Cactus Group are trying to explain the nature of QSS by using two conceptual frameworks, strictly related with the dynamical anomalies of the HMF model: the nonextensive statistical mechanics proposed by C.Tsallis, whose formalism well adapt to the study of long-range system far from equilibrium, and Spin-Glass models, characterized by aging, frustration and weak ergodicity breaking. Both these approaches seem to be applicable to the HMF context, since during the metastable QSS regime the system is not free to explore all the a-priori available phase space but results to be trapped into narrow fractal-like phase-space regions thus violating ergodicity prescription (see my PHD thesis for an overview on HMF model). All these features drive the HMF model towards a violation of the Central Limit Theorem, in agreement with a recent generalization of the latter theorem proposed by Tsallis, as we showed in some papers published with Tsallis himself.

My interest is also related to synchronization of coupled oscillators, for example in the context of the celebrate Kuramoto Model. Through extensive numerical simulations we found QSS-like metastable states in a given range of the coupling parameter, just below the second order phase transition.

We are working also on synchronization over complex networks, developing models of dynamical systems able to identify modular structures through the progressive desynchronization (dynamical clustering) of oscillators coupled with the nodes of the network. These researches find interesting applications in many fields, from genetics to neurobiology, from ecology to social science.

Recently we started to work on consensus formation and opnion dynamics in the context of the so called "Sociophysics", a new branch of statistical physics which deals with emergent phenomena in social science. We explored existing models, like the Heigselmann e Krause one, but also introduced a new model, inspired to Kuramoto and to the concept of "bounded confidence", the so called OCR (Opinion Changing Rate) model. Here opinions are represented as coupled oscillators with different natural frequencies, which represent different tendencies to change. Despite of these differences, opinions are able to synchronize - again above a given treshold of the coupling parameters - in order to reach consensus.

Actually, my interests in social systems go beyond these models and involve topics like Memetics (cultural replicators), the study of critical points in socio-economics systems and the field of emergent social entities known as social "Superorganisms" (click on the link to read a divulgative paper on this last topic).

Besides classical Fortran or C++ environments, I am recently developing applications with a new intriguing software running on Java platform and particularly oriented to Agent Based Models simulations. Its name is Netlogo, and it is freely downloadable from its web-site. It represents the ideal develop environment for the simulation of physical, biological or social systems, since it offers meny tools for treating complex systems made of many interacting units and for visualizing their significant parameters in real time. All the simulations you can find on this web site and on the Simulab section of the Cactus Group web site have been realized by us with this powerful software.

Last but not least, I am very attracted by the epistemological implications of Quantum Mechanics (see my answers to Ulisse - in italian -, on the SISSA website) and by alternative quantum theories, like Bohm-Vigier theory or SIMQ (Stocastic Interpretation of Quantum Mechanics). I am also interested in the Sintropic Phenomena theory of Fantappié, in the Psi Field theory of Laszlo and in the related theories of Preparata and Del Giudice, and also in exploring their experimental basis.

Note: The applets linked in this page (selected from Cactus Group Simulab) require Java Runtime Environment (Java 1.4.1 or higher). You may obtain the latest Java plugin from Sun's Java site.