{ "id": "1908.07502", "version": "v1", "published": "2019-08-20T17:27:12.000Z", "updated": "2019-08-20T17:27:12.000Z", "title": "Fractal dimension of critical curves in the $O(n)$-symmetric $φ^4$-model and crossover exponent at 6-loop order: Loop-erased random walks, self-avoiding walks, Ising, XY and Heisenberg models", "authors": [ "Mikhail Kompaniets", "Kay Joerg Wiese" ], "comment": "16 pages, 18 figures, 7 tables", "categories": [ "cond-mat.stat-mech", "hep-th" ], "abstract": "We calculate the fractal dimension $d_{\\rm f}$ of critical curves in the $O(n)$ symmetric $(\\vec \\phi^2)^2$-theory in $d=4-\\varepsilon$ dimensions at 6-loop order. This gives the fractal dimension of loop-erased random walks at $n=-2$, self-avoiding walks ($n=0$), Ising lines $(n=1)$, and XY lines ($n=2$), in agreement with numerical simulations. It can be compared to the fractal dimension $d_{\\rm f}^{\\rm tot}$ of all lines, i.e. backbone plus the surrounding loops, identical to $d_{\\rm f}^{\\rm tot} = 1/\\nu$. The combination $\\phi_{\\rm c}= d_{\\rm f}/d_{\\rm f}^{\\rm tot} = \\nu d_{\\rm f}$ is the crossover exponent, describing a system with mass anisotropy. Introducing a novel self-consistent resummation procedure, and combining it with analytic results in $d=2$ allows us to give improved estimates in $d=3$ for all relevant exponents at 6-loop order.", "revisions": [ { "version": "v1", "updated": "2019-08-20T17:27:12.000Z" } ], "analyses": { "keywords": [ "fractal dimension", "loop-erased random walks", "crossover exponent", "self-avoiding walks", "critical curves" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }