Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 18: Posters: Statistical Physics in Biological Systems

BP 18.26: Poster

Mittwoch, 28. März 2012, 17:30–19:30, Poster A

Non-Equilibrium Phase Transition in a Biofilm Growth Model — •Florentine Mayer and Erwin Frey — Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, Germany

Biofilms show remarkable resistance to environmental stress as, for example, introduced by antibiotics. This is because biofilms promote growth by diversifying cells: faster growing, more sensitive phenotypes are protected by resistant phenotypes. As environmental conditions change, the fitness of phenotypes may change, which increases the benefit of heterogeneous populations. While models for well-mixed systems reproduce the advantage of heterogeneity in changing environments, the situation for spatial settings has received less attention so far. To analyze biofilm growth we set up a two-species automaton model in which growth and death rates depend on the environmental conditions. These fluctuate, resulting in periodically interchanged growth and death rates of the two phenotypes. Depending on the rates we find either fast extinction or thriving biofilms with intriguing spatio-temporal patterns. Close to the region of extinction patterns become self-affine, which is the hallmark of a phase transition to an absorbing state (i.e. an empty lattice). Employing extensive stochastic simulations we measure critical exponents of our non-equilibrium phase transition and find universal scaling behavior, which characterises the universality class of our model.