title: Tailoring the interactions between self-propelled bodies.
abstract: We classify the interactions between self-propelled particles moving at a constant speed from symmetry considerations. We establish a systematic expansion for the two-body forces in the spirit of a multipolar expansion. This formulation makes it possible to rationalize most of the models introduced so far within a common framework. We distinguish between three classes of physical interactions: i) potential forces, ii) inelastic collisions and iii) non-reciprocal interactions involving polar or nematic alignment with an induced field. This framework provides simple design rules for the modeling and the fabrication of self-propelled bodies interacting via physical interactions. A class of possible interactions that should yield new phases of active matter is highlighted.
authors: Laboratoire de Physique de l'École Normale Supérieure de Lyon, Université de Lyon, 69007, Lyon, France, jeanbaptiste.caussin@ens-lyon.fr.
authors: Jean-Baptiste
authors: JB
authors: Caussin
authors: Denis
authors: D
authors: Bartolo
mesh_terms: D004548:Elasticity; D055595:Mechanical Phenomena; D008962:Models, Theoretical; D009038:Motion