Selective and collective actuation in active solids

Active solids consist of elastically coupled out-of-equilibrium units performing work. They are central to autonomous processes, such as locomotion, self-oscillations and rectification, in biological systems,designer materials robotics. Yet, the feedback mechanism between elastic active forces, possible emergence collective behaviours a mechanically stable solid remains elusive. Here we introduce minimal realization an solid, which characterize selective actuation fully map out interplay activity, elasticity geometry. Polar agents exert forces on nodes two dimensional lattice. The resulting displacement field nonlinearly reorients agents. For large enough coupling, oscillation lattice around their equilibrium position emerges. Only few modes actuated and, crucially, they not necessarily lowest energy ones. Combining experiments with numerical theoretical analysis model, unveil bifurcation scenario selection by takes place. Our findings may provide new for oscillatory dynamics tissues specifically confluent cell monolayers. present also be advantageous providing meta-materials, bona fide autonomy.