{ "id": "1510.00534", "version": "v1", "published": "2015-10-02T09:11:15.000Z", "updated": "2015-10-02T09:11:15.000Z", "title": "Partition function zeros for the Ising model on complete graphs and on annealed scale-free networks", "authors": [ "M. Krasnytska", "B. Berche", "Yu. Holovatch", "R. Kenna" ], "comment": "36 pages, 31 figures", "categories": [ "cond-mat.stat-mech", "cond-mat.dis-nn" ], "abstract": "We analyze the partition function of the Ising model on graphs of two different types: complete graphs, wherein all nodes are mutually linked and annealed scale-free networks for which the degree distribution decays as $P(k)\\sim k^{-\\lambda}$. We are interested in zeros of the partition function in the cases of complex temperature or complex external field (Fisher and Lee-Yang zeros respectively). For the model on an annealed scale-free network, we find an integral representation for the partition function which, in the case $\\lambda > 5$, reproduces the zeros for the Ising model on a complete graph. For $3<\\lambda < 5$ we derive the $\\lambda$-dependent angle at which the Fisher zeros impact onto the real temperature axis. This, in turn, gives access to the $\\lambda$-dependent universal values of the critical exponents and critical amplitudes ratios. Our analysis of the Lee-Yang zeros reveals a difference in their behaviour for the Ising model on a complete graph and on an annealed scale-free network when $3<\\lambda <5$. Whereas in the former case the zeros are purely imaginary, they have a non zero real part in latter case, so that the celebrated Lee-Yang circle theorem is violated.", "revisions": [ { "version": "v1", "updated": "2015-10-02T09:11:15.000Z" } ], "analyses": { "keywords": [ "annealed scale-free network", "complete graph", "ising model", "partition function zeros", "non zero real part" ], "publication": { "doi": "10.1088/1751-8113/49/13/135001", "journal": "Journal of Physics A Mathematical General", "year": 2016, "month": "Apr", "volume": 49, "number": 13, "pages": 135001 }, "note": { "typesetting": "TeX", "pages": 36, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2016JPhA...49m5001K" } } }