{ "id": "1802.07151", "version": "v1", "published": "2018-02-20T15:30:00.000Z", "updated": "2018-02-20T15:30:00.000Z", "title": "Exact results for the $O(N)$ model with quenched disorder", "authors": [ "Gesualdo Delfino", "Noel Lamsen" ], "categories": [ "cond-mat.stat-mech", "hep-th" ], "abstract": "We use scale invariant scattering theory to exactly determine the lines of renormalization group fixed points for $O(N)$-symmetric models with quenched disorder in two dimensions. Random fixed points are characterized by two disorder parameters: a modulus that vanishes when approaching the pure case, and a phase angle. The critical lines fall into three classes depending on the values of the disorder modulus. Besides the class corresponding to the pure case, a second class has maximal value of the disorder modulus and includes Nishimori-like multicritical points as well as zero temperature fixed points. The third class contains critical lines that interpolate, as $N$ varies, between the first two classes. For positive $N$, it contains a single line of infrared fixed points spanning the values of $N$ from $\\sqrt{2}-1$ to $1$. The symmetry sector of the energy density operator is superuniversal (i.e. $N$-independent) along this line. For $N=2$ a line of fixed points exists only in the pure case, but accounts also for the Berezinskii-Kosterlitz-Thouless phase observed in presence of disorder.", "revisions": [ { "version": "v1", "updated": "2018-02-20T15:30:00.000Z" } ], "analyses": { "keywords": [ "quenched disorder", "exact results", "pure case", "disorder modulus", "third class contains critical lines" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }