{ "id": "2005.12706", "version": "v1", "published": "2020-05-26T13:27:17.000Z", "updated": "2020-05-26T13:27:17.000Z", "title": "Edwards-Wilkinson fluctuations for the directed polymer in the full $L^2$-regime for dimensions $d \\geq 3$", "authors": [ "Dimitris Lygkonis", "Nikos Zygouras" ], "comment": "46 pages, 2 figures", "categories": [ "math.PR", "math-ph", "math.MP" ], "abstract": "We prove that in the full $L^2$-regime the partition function of the directed polymer model in dimensions $d\\geq 3$, if centered, scaled and averaged with respect to a test function $\\varphi \\in C_c(\\mathbb{R}^d)$, converges in distribution to a Gaussian random variable with explicit variance. Introducing a new idea of a martingale difference representation, we also prove that the log-partition function, which can be viewed as a discretisation of the KPZ equation, exhibits the same fluctuations, when centered and averaged with respect to a test function. Thus, the two models fall within the Edwards-Wilkinson universality class in the full $L^2$-regime, a result that was only established, so far, for a strict subset of this regime in $d\\geq 3$.", "revisions": [ { "version": "v1", "updated": "2020-05-26T13:27:17.000Z" } ], "analyses": { "keywords": [ "edwards-wilkinson fluctuations", "dimensions", "test function", "martingale difference representation", "edwards-wilkinson universality class" ], "note": { "typesetting": "TeX", "pages": 46, "language": "en", "license": "arXiv", "status": "editable" } } }