Diffusive properties of Brownian agents interacting via metric-free aligning-forces*

The diffusive properties of active particles moving at constant speed in two dimensions andinteracting through metric-free aligning-forces are studied. Exponential and scale free networks are used as the backbone for the interactions among agents. Averages over the trajectories of hundred thousand agents are performed to compute the single particle mean-square displacement, and the kurtosis of the spatial distribution, as a function of time. These quantities provide a mean to evaluate the effects of interaction. In contrast to what one would expect, the diffusion constant, increases with the intensity of the alignment.