Seminars & Colloquia Calendar

Abstract: Biological groups such as insect swarms and bird flocks are considered as paradigmatic examples of `active' living matter, where self-propelled interacting individuals give rise to collective patterns over large scales. Activity, i.e. the ability of individuals to convert energy into motion, is a crucial feature of these systems. Experiments and theoretical analysis show that - combined with interactions - activity enhances ordering and gives rise to a novel class of dynamic critical behaviour. Activity is primarily related to energy injection and it drives the system out of equilibrium. In this talk, using simple models of collective motion, I will discuss how to quantify the departure from equilibrium in polar active systems, and how to connect it with the emergence of spontaneous order and collective response. I will finally show that signatures of irreversibility can be directly measured from the data and manifest as asymmetries in the two-body distribution.