Noise-induced breakdown of coherent collective motion in swarms

We consider swarms formed by populations of self-propelled particles with a ttractive long-range interactions. These swarms represent multistable dynam ical systems and can be found either in coherent traveling states or in an incoherent oscillatory state where translational motion of the entire swarm is absent. Under increasing the noise intensity, the coherent traveling st ate of the swarms is destroyed and an abrupt transition to the oscillatory state takes place. [S1063-651X(99)11309-6].