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LA Probability Forum

Thursday, March 9, 2023
6:00pm to 7:00pm
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Chemical distances for long-range percolation
Johannes Bäumler, Technical University of Munich,

UCLA - Math Sciences Room 6627

Consider long-range percolation on $\mathbb{Z}^d$, where there is an edge between two points $x$ and $y$ with probability asymptotic to $\beta \|x-y\|^{-s}$, independent of all other edges, for some positive parameters $s$ and $\beta$. In this talk, we will focus on the metric properties of the long-range percolation graph. The chemical distance between two points $x$ and $y$ is the number of steps one needs to make in order to go from $x$ to $y$. For different values of $s$, there are different regimes of how the chemical distance scales with the Euclidean distance. The transitions between these regimes happen at $s=d$ and $s=2d$. After an overview of previous work, we will focus on the case $s=2d$. We will show that for $s=2d$, for each dimension $d$ and for each $\beta > 0$, there exists a $\theta=\theta(d,\beta) \in (0,1)$ such that the chemical distance between $x$ and $y$ is of order $\|x-y\|^{\theta}$. We will also discuss how the exponent $\theta$ depends on the parameter $\beta$.

For more information, please contact Math Dept by phone at 626-395-4335 or by email at mathinfo@caltech.edu.