{ "id": "cond-mat/0603218", "version": "v1", "published": "2006-03-08T16:45:33.000Z", "updated": "2006-03-08T16:45:33.000Z", "title": "Is it really possible to grow isotropic on-lattice diffusion-limited aggregates?", "authors": [ "S. G. Alves", "S. C. Ferreira Jr" ], "comment": "12 pages, 8 figures", "journal": "J. Phys. A: Math. Gen. 39 (2006) 2843-2852", "doi": "10.1088/0305-4470/39/12/001", "categories": [ "cond-mat.stat-mech" ], "abstract": "In a recent paper (Bogoyavlenskiy V A 2002 \\JPA \\textbf{35} 2533), an algorithm aiming to generate isotropic clusters of the on-lattice diffusion-limited aggregation (DLA) model was proposed. The procedure consists of aggregation probabilities proportional to the squared number of occupied sites ($k^2$). In the present work, we analyzed this algorithm using the noise reduced version of the DLA model and large scale simulations. In the noiseless limit, instead of isotropic patterns, a $45^\\circ$ ($30^\\circ$) rotation in the anisotropy directions of the clusters grown on square (triangular) lattices was observed. A generalized algorithm, in which the aggregation probability is proportional to $k^\\nu$, was proposed. The exponent $\\nu$ has a nonuniversal critical value $\\nu_c$, for which the patterns generated in the noiseless limit exhibit the original (axial) anisotropy for $\\nu<\\nu_c$ and the rotated one (diagonal) for $\\nu>\\nu_c$. The values $\\nu_c = 1.395\\pm0.005$ and $\\nu_c = 0.82\\pm 0.01$ were found for square and triangular lattices, respectively. Moreover, large scale simulations show that there are a nontrivial relation between noise reduction and anisotropy direction. The case $\\nu=2$ (\\bogo's rule) is an example where the patterns exhibit the axial anisotropy for small and the diagonal one for large noise reduction.", "revisions": [ { "version": "v1", "updated": "2006-03-08T16:45:33.000Z" } ], "analyses": { "keywords": [ "grow isotropic on-lattice diffusion-limited aggregates", "large scale simulations", "anisotropy direction", "noise reduction", "aggregation probability" ], "tags": [ "journal article" ], "publication": { "journal": "Journal of Physics A Mathematical General", "year": 2006, "month": "Mar", "volume": 39, "number": 12, "pages": 2843 }, "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006JPhA...39.2843A" } } }