Generic theory of interacting, spinning, active polar particles: a model for cell aggregates

We present a generic framework for describing interacting, spinning, active polar particles, aimed at modelling dense cell aggregates, where cells are treated as polar, rotating objects that interact mechanically with one another and their surrounding environment. Using principles from non-equilibrium thermodynamics, we derive constitutive equations for interaction forces, torques, and polarity dynamics. We subsequently use this framework to analyse the spontaneous motion of cell doublets, uncovering a rich phase diagram of collective behaviours, including steady rotation driven by flow-polarity coupling or interactions between polarity and cell position.