New lower bounds for the (near) critical Ising and $φ^4$ models' two-point functions

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Auteurs principaux: Duminil-Copin, Hugo, Panis, Romain
Format: Preprint
Publié: 2024
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author Duminil-Copin, Hugo
Panis, Romain
author_facet Duminil-Copin, Hugo
Panis, Romain
contents We study the nearest-neighbour Ising and $φ^4$ models on $\mathbb Z^d$ with $d\geq 3$ and obtain new lower bounds on their two-point functions at (and near) criticality. Together with the classical infrared bound, these bounds turn into up-to constant estimates when $d\geq 5$. When $d=4$, we obtain an ''almost'' sharp lower bound corrected by a logarithmic factor. As a consequence of these results, we show that $η=0$ and $ν=1/2$ when $d\geq 4$, where $η$ is the critical exponent associated with the decay of the model's two-point function at criticality and $ν$ is the critical exponent of the correlation length $ξ(β)$. When $d=3$, we improve previous results and obtain that $η\leq 1/2$. As a byproduct of our proofs, we also derive the blow-up at criticality of the so-called bubble diagram when $d=3,4$.
format Preprint
id arxiv_https___arxiv_org_abs_2404_05700
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle New lower bounds for the (near) critical Ising and $φ^4$ models' two-point functions
Duminil-Copin, Hugo
Panis, Romain
Probability
Mathematical Physics
60K35, 82B20, 82B27
We study the nearest-neighbour Ising and $φ^4$ models on $\mathbb Z^d$ with $d\geq 3$ and obtain new lower bounds on their two-point functions at (and near) criticality. Together with the classical infrared bound, these bounds turn into up-to constant estimates when $d\geq 5$. When $d=4$, we obtain an ''almost'' sharp lower bound corrected by a logarithmic factor. As a consequence of these results, we show that $η=0$ and $ν=1/2$ when $d\geq 4$, where $η$ is the critical exponent associated with the decay of the model's two-point function at criticality and $ν$ is the critical exponent of the correlation length $ξ(β)$. When $d=3$, we improve previous results and obtain that $η\leq 1/2$. As a byproduct of our proofs, we also derive the blow-up at criticality of the so-called bubble diagram when $d=3,4$.
title New lower bounds for the (near) critical Ising and $φ^4$ models' two-point functions
topic Probability
Mathematical Physics
60K35, 82B20, 82B27
url https://arxiv.org/abs/2404.05700