SKM 2023 – wissenschaftliches Programm
DY 44.14: Poster
Donnerstag, 30. März 2023, 13:00–16:00, P1
Dividing Active Brownian Particles — •Till Welker and Holger Stark — Institut für Theoretische Physik, Technische Universität Berlin, Germany.
We aim to combine active motion with cell division to answer questions like: Does nutrient input induce clustering? How does a non-uniform nutrient distribution effects population dynamics?
To include cell division and death in the model of active Brownian particles, we propose a simple rule: in a time interval dt, each particle has a probability dt · g(s) to divide and dt · d to die. The growth rate g depends on the nutrient concentration s at the position of the bacterium and is described by the Monod function. The nutrient diffuses with the diffusion coefficient DN. We add a source with steady input rate S0, in addition, each particle takes up nutrient with a rate γ g(s).
The population dynamics strongly depends on nutrient diffusion: For large DN, the population oscillates before reaching a steady population number N*. For small DN, the population is stronger damped and equilibrates quickly. N* is independent of DN, but the population fluctuation decreases for lower DN due to the damping. The collective behavior is also influenced by the nutrient: First, for large DN the swarm has a strongly asymmetric shape during the transient phase which then becomes symmetric in the steady state. Second, the swarm is less dense for larger DN, but the relationship between spread of nutrient and bacteria is not linear.
We show that combining two key aspects of microbial life, mobility and growth, gives rise to interesting population and spatial dynamics.