| We analyze a model of active Brownian particles with velocity alignment in one and two spatial dimensions. The model exhibits two modes of motion observed in biological swarms: A disordered phase with vanishing mean velocity and an ordered phase with finite mean velocity. Starting from the microscopic Langevin equations we derive mean field equations for the collective dynamics via a nonlinear Fokker-Planck equation. We discuss the corresponding mean field solutions and compare them with numerical results. Hereby we focus on the impact of different active propulsion functions and fluctuations types determining the dynamics of individuals on the onset and stability of collective motion. |
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