Evidence of a robust universality class in the critical behavior of self-propelled agents: Metric versus topological interactions

L. BARBERIS; E V ALBANO

PHYSICAL REVIEW E - STATISTICAL PHYSICS, PLASMAS, FLUIDS AND RELATED INTERDISCIPLINARY TOPICS

APS

Año: 2014 vol. 89 p. 12139 - 12145

1063-651X

The nature of the interactions among self-propelled agents (SPA), i.e., topological versus metric or acombination of both types, is a relevant open question in the field of self-organization phenomena. We studiedthe critical behavior of a Vicsek-like system of SPA given by a group of agents moving at constant speed andinteracting among themselves under the action of a topological rule: each agent aligns itself with the averagedirection of its seven nearest neighbors, independent of the distance, under the influence of some noise. Basedon both stationary and dynamic measurements, we provide strong evidence that both types of interactionsare manifestations of the same phenomenon, which defines a robust universality class. Also, the cluster sizedistribution evaluated at the critical point shows a power-law behavior, and the exponent corresponding to thetopological model is in excellent agreementwith that of themetric one, further reinforcing our claim. Furthermore,we found that with topological interactions the average distance of influence between agents undergoes largefluctuations that diverge at the critical noise, thus providing clues about a mechanism that could be implementedby the agents to change their moving strategy.