{ "id": "1306.6543", "version": "v1", "published": "2013-06-27T15:17:11.000Z", "updated": "2013-06-27T15:17:11.000Z", "title": "The two-point correlation function of the fractional parts of \\sqrt{n} is Poisson", "authors": [ "Daniel El-Baz", "Jens Marklof", "Ilya Vinogradov" ], "comment": "15 pages, 3 figures", "categories": [ "math.NT", "math.DS" ], "abstract": "Elkies and McMullen [Duke Math.J.~123 (2004) 95--139] have shown that the gaps between the fractional parts of \\sqrt n for n=1,\\ldots,N, have a limit distribution as N tends to infinity. The limit distribution is non-standard and differs distinctly from the exponential distribution expected for independent, uniformly distributed random variables on the unit interval. We complement this result by proving that the two-point correlation function of the above sequence converges to a limit, which in fact coincides with the answer for independent random variables. We also establish the convergence of moments for the probability of finding r points in a randomly shifted interval of size 1/N. The key ingredient in the proofs is a non-divergence estimate for translates of certain non-linear horocycles.", "revisions": [ { "version": "v1", "updated": "2013-06-27T15:17:11.000Z" } ], "analyses": { "subjects": [ "11J71", "11K36", "11P21", "22E40", "37A17", "37A25" ], "keywords": [ "two-point correlation function", "fractional parts", "limit distribution", "independent random variables", "uniformly distributed random variables" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1306.6543E" } } }