{ "id": "1612.08809", "version": "v1", "published": "2016-12-28T06:34:20.000Z", "updated": "2016-12-28T06:34:20.000Z", "title": "Mean-field bound on the 1-arm exponent for Ising ferromagnets in high dimensions", "authors": [ "Satoshi Handa", "Markus Heydenreich", "Akira Sakai" ], "comment": "14 pages, 1 figure", "categories": [ "math-ph", "math.MP", "math.PR" ], "abstract": "The 1-arm exponent $\\rho$ for the ferromagnetic Ising model on $\\mathbb{Z}^d$ is the critical exponent that describes how fast the critical 1-spin expectation at the center of the ball of radius $r$ surrounded by plus spins decays in powers of $r$. Suppose that the spin-spin coupling $J$ is translation-invariant, $\\mathbb{Z}^d$-symmetric and finite-range. Using the random-current representation and assuming the anomalous dimension $\\eta=0$, we show that the optimal mean-field bound $\\rho\\le1$ holds for all dimensions $d>4$. This significantly improves a bound previously obtained by a hyperscaling inequality.", "revisions": [ { "version": "v1", "updated": "2016-12-28T06:34:20.000Z" } ], "analyses": { "keywords": [ "high dimensions", "ising ferromagnets", "optimal mean-field bound", "plus spins decays", "random-current representation" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }