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arXiv · 1604.02994

Convergence to a single wave in the Fisher-KPP equation

James Nolen·Jean-Michel Roquejoffre·Lenya Ryzhik
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Abstract

We study the large time asymptotics of a solution of the Fisher-KPP reaction-diffusion equation, with an initial condition that is a compact perturbation of a step function. A well-known result of Bramson states that, in the reference frame moving as $2t - ({3}/{2}) \log t +x_\infty$, the solution of the equation converges as $t\to+\infty$ to a translate of the traveling wave corresponding to the minimal speed~$c_*=2$. The constant $x_\infty$ depends on the initial condition $u(0,x)$. The proof is elaborate, and based on probabilistic arguments. The purpose of this paper is to provide a simple proof based on PDE arguments.

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James Nolen, Jean-Michel Roquejoffre, Lenya Ryzhik. 2016-06-17. Convergence to a single wave in the Fisher-KPP equation. https://arxiv.org/abs/1604.02994

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