{ "id": "2002.00618", "version": "v1", "published": "2020-02-03T09:26:44.000Z", "updated": "2020-02-03T09:26:44.000Z", "title": "Combinatorics of 3D directed animals on a simple cubic lattice", "authors": [ "Sergei Nechaev", "Michael Tamm" ], "comment": "7 pages, 6 figures", "categories": [ "cond-mat.stat-mech", "hep-th", "math.CO" ], "abstract": "We provide combinatorial arguments based on a two-dimensional extension of a locally-free semigroup allowing us to compute the growth rate, $\\Lambda$, of the partition function $Z_N=N^{\\theta}\\Lambda^N$ of the $N$-particle directed animals ($N\\gg 1$) on a simple cubic lattice in a three-dimensional space. Establishing the bijection between the particular configuration of the lattice animal and a class of equivalences of words in the 2D projective locally-free semigroup, we find we find $\\ln \\Lambda = \\lim_{N\\to\\infty} \\ln Z_N / N$ with $\\Lambda= 2(\\sqrt{2}+1) \\approx 4.8284$.", "revisions": [ { "version": "v1", "updated": "2020-02-03T09:26:44.000Z" } ], "analyses": { "keywords": [ "simple cubic lattice", "3d directed animals", "combinatorics", "2d projective locally-free semigroup", "two-dimensional extension" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable" } } }