{ "id": "1607.08802", "version": "v1", "published": "2016-07-29T13:34:44.000Z", "updated": "2016-07-29T13:34:44.000Z", "title": "Refined long time asymptotics for Fisher-KPP fronts", "authors": [ "James Nolen", "Jean-Michel Roquejoffre", "Lenya Ryzhik" ], "comment": "20 pages", "categories": [ "math.AP" ], "abstract": "We study the one-dimensional Fisher-KPP equation, with an initial condition $u_0(x)$ that coincides with the step function except on a compact set. A well-known result of M. Bramson states that, as $t\\to+\\infty$, the solution converges to a traveling wave located at the position $X(t)=2t-(3/2)\\log t+x_0+o(1)$, with the shift $x_0$ that depends on $u_0$. U. Ebert and W. Van Saarloos have formally derived a correction to the Bramson shift, arguing that $X(t)=2t-(3/2)\\log t+x_0-3\\sqrt{\\pi}/\\sqrt{t}+O(1/t)$. Here, we prove that this result does hold, with an error term of the size $O(1/t^{1-\\gamma})$, for any $\\gamma>0$. The interesting aspect of this asymptotics is that the coefficient in front of the $1/\\sqrt{t}$-term does not depend on $u_0$.", "revisions": [ { "version": "v1", "updated": "2016-07-29T13:34:44.000Z" } ], "analyses": { "subjects": [ "35K57", "35C07", "35B40" ], "keywords": [ "refined long time asymptotics", "fisher-kpp fronts", "one-dimensional fisher-kpp equation", "bramson states", "bramson shift" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable" } } }