Self-aligning polar active matter

Abstract

What if active units could align--or even antialign--their orientation with their own velocity? This intriguing self-alignment property unlocks a spectrum of fascinating behaviors, from single self-propelled particles orbiting in harmonic traps to transformative collective phenomena like synchronized motion in dense or solid elastic assemblies. Unlike systems where units simply mimic their neighbors, self-alignment fundamentally reshapes how motion emerges, paving the way for groundbreaking discoveries in biology, smart materials, and robotics. This review uncovers the hidden power of self-alignment in active systems, introduces a unified mathematical and conceptual framework, explores existing models of self-alignment, and highlights its transformative impact on the study and real-world applications of active systems.