Collective patterns of swarm dynamics and the Lyapunov analysis of individual behaviors

In this report, the collective patterns of swarms dynamics are theoretically studied using a self-propelled particle model, and the dynamics of the individual particles in the swarms is precisely studied using Lyapunov analysis. Furthermore, the collective behaviors of the swarms are classified into several patterns characterized by the following statistical quantities: Lyapunov spectrum, Lyapunov dimension, and stability and instability indices. Consequently, we propose individual instability exponents (IIEs) that describes the sensitivity of the individual particles in the swarm, and show that the IIEs is a significant order parameter that demonstrates changes in the pattern and expresses the activity of the swarm dynamics. Furthermore, we show that the mean and variance obtained after calculating the speed distribution of individual particles reveal marked variations corresponding to the change in the pattern in a manner similar to those of the IIEs.