73 research outputs found

    On rates of convergence for the overlap in the Hopfield model

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    We consider the Hopfield model with nn neurons and an increasing number p=p(n)p=p(n) of randomly chosen patterns and use Stein's method to obtain rates of convergence for the central limit theorem of overlap parameters, which holds for every fixed choice of the overlap parameter for almost all realisations of the random patterns.Comment: 19 page

    Stein's method for dependent random variables occurring in Statistical Mechanics

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    We obtain rates of convergence in limit theorems of partial sums SnS_n for certain sequences of dependent, identically distributed random variables, which arise naturally in statistical mechanics, in particular, in the context of the Curie-Weiss models. Under appropriate assumptions there exists a real number α\alpha, a positive real number μ\mu, and a positive integer kk such that (Snnα)/n11/2k(S_n- n \alpha)/n^{1 - 1/2k} converges weakly to a random variable with density proportional to exp(μx2k/(2k)!)\exp(-\mu |x|^{2k} /(2k)!). We develop Stein's method for exchangeable pairs for a rich class of distributional approximations including the Gaussian distributions as well as the non-Gaussian limit distributions with density proportional to exp(μx2k/(2k)!)\exp(-\mu |x|^{2k} /(2k)!). Our results include the optimal Berry-Esseen rate in the Central Limit Theorem for the total magnetization in the classical Curie-Weiss model, for high temperatures as well as at the critical temperature βc=1\beta_c=1, where the Central Limit Theorem fails. Moreover, we analyze Berry-Esseen bounds as the temperature 1/βn1/ \beta_n converges to one and obtain a threshold for the speed of this convergence. Single spin distributions satisfying the Griffiths-Hurst-Sherman (GHS) inequality like models of liquid helium or continuous Curie-Weiss models are considered
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