Nonamenable Poisson zoo
Abstract
In the Poisson zoo on an infinite Cayley graph , we take a probability measure on rooted finite connected subsets, called lattice animals, and place i.i.d. Poisson() copies of them at each vertex. If the expected volume of the animals w.r.t. is infinite, then the whole is covered for any . If the second moment of the volume is finite, then it is easy to see that for small enough the union of the animals has only finite clusters, while for large enough there are also infinite clusters. Here we show that: 1. If is a nonamenable free product, then for ANY with infinite second but finite first moment and any , there will be infinite clusters, despite having arbitrarily low density. 2. The same result holds for ANY nonamenable , when the lattice animals are worms: random walk pieces of random finite length. It remains open if the result holds for ANY nonamenable Cayley graph with ANY lattice animal measure with infinite second moment. 3. We also give a Poisson zoo example on with finite first moment and a UNIQUE infinite cluster for any .
Keywords
Cite
@article{arxiv.2505.07145,
title = {Nonamenable Poisson zoo},
author = {Gábor Pete and Sándor Rokob},
journal= {arXiv preprint arXiv:2505.07145},
year = {2025}
}
Comments
40 pages, 4 figures