Socioeconomic agents as active matter and nucleation paths in active field theories
Ruben Zakine (Ecole Polytechnique)
In this seminar, we will tackle two subjects whose common thread is active matter.
In a first part, I will focus on a socio-economic occupation model in the spirit of the Sakoda-Schelling model, historically introduced to shed light on segregation dynamics among human groups. For a large class of utility functions and decision rules that drive the system out of equilibrium, we recover an equilibrium-like phase separation phenomenology. Within the mean-field approximation I will show how the model can be mapped, to some extent, onto an active matter field description, paving the way for a unifying framework which considers population and price dynamics within a field theoretic approach.
In a second part, using the nucleation-induced active phase separation as a starting observation, I will ask a general question: How can one predict the final phase of a nonequilibrium system where several phases compete? Since resorting to the free energy minimization is impossible, the transition depends crucially on the system’s dynamics. By using a minimum action method, we will pinpoint the first-order phase transition in some spatially-extended nonequilibrium systems, including the Active Model B, the natural nonequilibrium extension of the Cahn-Hilliard dynamics. The paths of the transitions and their critical nuclei are notably identified
Meeting ID: 922 5447 7857