Universitá de la Spienza, Italy
Out of equilibrium behavior and dynamical mode coupling in the collective motion of biological groups
Recent findings on flocks of birds and swarms of insects show that these groups exhibit strong correlations and obey static and dynamic scaling laws, thereby supporting a statistical physics approach. When modelling these systems, activity is a fundamental trait, responsible for out-of-equilibrium properties on the large scale. Experiments however indicate that another crucial ingredient - behavioural inertia - is needed to reproduce the observed phenomenology. In this talk, after reviewing the experimental facts, I will discuss how these two ingredients can be appropriately incorporated in the theoretical description, both in microscopic models and at a coarse-grained level. The related field theory, including both dissipative and reversible dynamical terms, displays non-trivial collective dynamics, and its predictions are consistent with what observed in natural groups.