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BP: Fachverband Biologische Physik
BP 6: Statistical Physics of Biological Systems II (joint DY, BP)
BP 6.3: Talk
Monday, March 14, 2011, 14:45–15:00, HÜL 186
Strong Noise Effects in one-dimensional Neutral Populations — •Luca Dall'Asta1, Fabio Caccioli2, and Deborah Beghè3 — 1ICTP, Trieste, Italy — 2Santa Fe Institute, Santa Fe, NM — 3Università di Parma, Parma, Italy
The dynamics of well-mixed biological populations is studied using mean-field methods and weak- noise expansions. Similar methods have been applied also in spatially extended problems, relying on the fact that these populations are organized in colonies with a large local density of individuals. We provide a counterexample discussing a one-dimensional neutral population with negative frequency- dependent selection. The system exhibits a continuous phase transition between genetic fixation and coexistence that is unexpected from weak-noise arguments. We show that the behavior is a non-perturbative effect of the internal noise that is amplified by presence of spatial correlations (strong- noise regime).