Relations between scaling exponents in unimodular random graphs
Relations between scaling exponents in unimodular random graphs
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DOI:
10.1007/s00039-023-00654-7
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发表时间:
2020-07
影响因子:
2.2
通讯作者:
James R. Lee
中科院分区:
文献类型:
--
作者:
James R. Lee
We investigate the validity of the “Einstein relations” in the general setting of unimodular random networks. These are equalities relating scaling exponents: \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$\begin{aligned} d_{w} &= d_{f} + \tilde{\zeta }, \\ d_{s} &= 2 d_{f}/d_{w}, \end{aligned}$$ \end{document} wheredwis the walk dimension,dfis the fractal dimension,dsis the spectral dimension, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\tilde{\zeta }$\end{document} is the resistance exponent. Roughly speaking, this relates the mean displacement and return probability of a random walker to the density and conductivity of the underlying medium. We show that ifdfand \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\tilde{\zeta } \geqslant 0$\end{document} exist, thendwanddsexist, and the aforementioned equalities hold. Moreover, our primary new estimate \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$d_{w} \geqslant d_{f} + \tilde{\zeta }$\end{document} is established for all \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\tilde{\zeta } \in \mathbb{R}$\end{document}.For the uniform infinite planar triangulation (UIPT), this yields the consequencedw=4 usingdf=4 (Angel in Geom. Funct. Anal. 13(5):935–974, ) and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\tilde{\zeta }=0$\end{document} (established here as a consequence of the Liouville Quantum Gravity theory, following Gwynne-Miller 2020 and (Ding and Gwynne in Commun. Math. Phys. 374(3):1877–1934, )). The conclusiondw=4 had been previously established by Gwynne and Hutchcroft (2018) using more elaborate methods. A new consequence is thatdw=dffor the uniform infinite Schnyder-wood decorated triangulation, implying that the simple random walk is subdiffusive, sincedf>2.