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When does the chaos in the Curie-Weiss model stop to propagate?

Probability 2023-07-12 v1 Mathematical Physics math.MP

Abstract

We investigate increasing propagation of chaos for the mean-field Ising model of ferromagnetism (also known as the Curie-Weiss model) with NN spins at inverse temperature β>0\beta>0 and subject to an external magnetic field of strength hRh\in\mathbb{R}. Using a different proof technique than in [Ben Arous, Zeitouni; 1999] we confirm the well-known propagation of chaos phenomenon: If k=k(N)=o(N)k=k(N)=o(N) as NN\to\infty, then the kk'th marginal distribution of the Gibbs measure converges to a product measure at β<1\beta <1 or h0h \neq 0 and to a mixture of two product measures, if β>1\beta >1 and h=0h =0. More importantly, we also show that if k(N)/Nα(0,1]k(N)/N\to \alpha\in (0,1], this property is lost and we identify a non-zero limit of the total variation distance between the number of positive spins among any kk-tuple and the corresponding binomial distribution.

Keywords

Cite

@article{arxiv.2307.05335,
  title  = {When does the chaos in the Curie-Weiss model stop to propagate?},
  author = {Jonas Jalowy and Zakhar Kabluchko and Matthias Löwe and Alexander Marynych},
  journal= {arXiv preprint arXiv:2307.05335},
  year   = {2023}
}

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