{ "id": "0711.4487", "version": "v1", "published": "2007-11-28T12:37:54.000Z", "updated": "2007-11-28T12:37:54.000Z", "title": "Generalized Diffusion", "authors": [ "James F. Lutsko", "Jean Pierre Boon" ], "comment": "29 pages, 8 figures", "journal": "PHYSICAL REVIEW E 77, 051103 2008", "doi": "10.1103/PhysRevE.77.051103", "categories": [ "cond-mat.stat-mech", "cond-mat.mtrl-sci", "cond-mat.soft" ], "abstract": "The Fokker-Planck equation for the probability $f(r,t)$ to find a random walker at position $r$ at time $t$ is derived for the case that the the probability to make jumps depends nonlinearly on $f(r,t)$. The result is a generalized form of the classical Fokker-Planck equation where the effects of drift, due to a violation of detailed balance, and of external fields are also considered. It is shown that in the absence of drift and external fields a scaling solution, describing anomalous diffusion, is only possible if the nonlinearity in the jump probability is of the power law type ($\\sim f^{\\eta }(r,t)$), in which case the generalized Fokker-Planck equation reduces to the well-known Porous Media equation. Monte-Carlo simulations are shown to confirm the theoretical results.", "revisions": [ { "version": "v1", "updated": "2007-11-28T12:37:54.000Z" } ], "analyses": { "subjects": [ "05.40.Fb", "05.60.-k", "05.10.Gg" ], "keywords": [ "generalized diffusion", "external fields", "power law type", "generalized fokker-planck equation reduces", "well-known porous media equation" ], "tags": [ "journal article" ], "publication": { "publisher": "APS", "journal": "Physical Review E", "year": 2008, "month": "May", "volume": 77, "number": 5, "pages": "051103" }, "note": { "typesetting": "TeX", "pages": 29, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008PhRvE..77e1103L" } } }