Ulrik Thinggaard Hansen, Boris Kjær, Frederik Ravn Klausen
{"title":"The Uniform Even Subgraph and Its Connection to Phase Transitions of Graphical Representations of the Ising Model","authors":"Ulrik Thinggaard Hansen, Boris Kjær, Frederik Ravn Klausen","doi":"10.1007/s00220-025-05297-3","DOIUrl":null,"url":null,"abstract":"<div><p>The uniform even subgraph is intimately related to the Ising model, the random-cluster model, the random current model, and the loop <span>\\(\\textrm{O}\\)</span>(1) model. In this paper, we first prove that the uniform even subgraph of <span>\\(\\mathbb {Z}^d\\)</span> percolates for <span>\\(d \\ge 2\\)</span> using its characterisation as the Haar measure on the group of even graphs. We then tighten the result by showing that the loop <span>\\(\\textrm{O}\\)</span>(1) model on <span>\\(\\mathbb {Z}^d\\)</span> percolates for <span>\\(d \\ge 2\\)</span> for edge-weights <i>x</i> lying in some interval <span>\\((1-\\varepsilon ,1]\\)</span>. Finally, our main theorem is that the loop <span>\\(\\textrm{O}\\)</span>(1) model and random current models corresponding to a supercritical Ising model are always at least critical, in the sense that their two-point correlation functions decay at most polynomially and the expected cluster sizes are infinite.</p></div>","PeriodicalId":522,"journal":{"name":"Communications in Mathematical Physics","volume":"406 6","pages":""},"PeriodicalIF":2.2000,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00220-025-05297-3.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Communications in Mathematical Physics","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s00220-025-05297-3","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MATHEMATICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The uniform even subgraph is intimately related to the Ising model, the random-cluster model, the random current model, and the loop \(\textrm{O}\)(1) model. In this paper, we first prove that the uniform even subgraph of \(\mathbb {Z}^d\) percolates for \(d \ge 2\) using its characterisation as the Haar measure on the group of even graphs. We then tighten the result by showing that the loop \(\textrm{O}\)(1) model on \(\mathbb {Z}^d\) percolates for \(d \ge 2\) for edge-weights x lying in some interval \((1-\varepsilon ,1]\). Finally, our main theorem is that the loop \(\textrm{O}\)(1) model and random current models corresponding to a supercritical Ising model are always at least critical, in the sense that their two-point correlation functions decay at most polynomially and the expected cluster sizes are infinite.
期刊介绍:
The mission of Communications in Mathematical Physics is to offer a high forum for works which are motivated by the vision and the challenges of modern physics and which at the same time meet the highest mathematical standards.