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On the analogy between self-gravitating Brownian particles and bacterial populations. (English) Zbl 1055.92005

Biler, Piotr (ed.) et al., Nonlocal elliptic and parabolic problems. Papers of the conference, Bȩdlewo, Poland, September 12–15, 2003. Warsaw: Polish Academy of Sciences, Institute of Mathematics. Banach Center Publications 66, 103-126 (2004).
Summary: We develop the analogy between self-gravitating Brownian particles and bacterial populations. In the high friction limit, the self-gravitating Brownian gas is described by the Smoluchowski-Poisson system. These equations can develop a self-similar collapse leading to a finite time singularity. Coincidentally, the Smoluchowski-Poisson system corresponds to a simplified version of the Keller-Segel model of bacterial populations. In this biological context, it describes the chemotactic aggregation of the bacterial colonies.
We extend these classical models by introducing a small-scale regularization. In the gravitational context, we consider a gas of self-gravitating Brownian fermions and in the biological context we consider finite size effects. In that case, the collapse stops when the system feels the influence of the small-scale regularization. A phenomenon of “explosion”, reverse to the collapse, is also possible.
For the entire collection see [Zbl 1052.35002].

MSC:

92C17 Cell movement (chemotaxis, etc.)
60J70 Applications of Brownian motions and diffusion theory (population genetics, absorption problems, etc.)
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