A Physical Approach to Swarming

Abstract

The previous chapter was centered on awe-inspiring collective behaviors observed in the animal kingdom, and how this inspirational bounty can be harnessed to develop innovative swarm designs. We stressed two important points related to some very common collective behaviors: (1) they occur across vastly different spatial scales—from the microscale world to our macroscale world, and (2) they emerge across immensely different taxa—from bacteria to quadrupeds. When faced with such empirical evidences, the physicist will immediately suggest the existence of universal mechanisms at the root of collective phenomena that would justify and explain such commonalities in dynamic behaviors. This may appear counterintuitive at first since the fundamental laws of physics yield forces and energies of very different magnitudes across a wide range of scales. For instance, swimming at the micrometer scale requires aggregating microorganisms—e.g. bacteria or amoebae—to power themselves by harnessing viscous forces which form the main source of drag for macroscale schooling fish. The undeniable successes of physics in the past centuries certainly come from an uninterrupted search for universality across seemingly unrelated phenomena—e.g. dispersion in optical waves and dispersion in mechanical waves. It comes therefore with no surprise that physicists have been extremely active, and successful, in the past two decades uncovering the prominent universal mechanisms at play in collective phenomena at large. This chapter will present a brief overview of those while stressing their importance for the designer of swarming systems.