Mixing cutoff for simple random walks on the Chung-Lu digraph

Fuente: arXiv
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Main Authors: Bianchi, Alessandra, Passuello, Giacomo
Format: Preprint
Published: 2024
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author Bianchi, Alessandra
Passuello, Giacomo
author_facet Bianchi, Alessandra
Passuello, Giacomo
contents In this paper, we are interested in the mixing behaviour of simple random walks on inhomogeneous directed graphs. We focus our study on the Chung-Lu digraph, which is an inhomogeneous network that generalizes the Erdős-Rényi digraph. In particular, under the Chung-Lu model, edges are included in the graph independently and according to given Bernoulli laws, so that the average degrees are fixed. To guarantee the a.s. existence of a unique reversible measure, which is implied by the strong connectivity of the graph, we assume that the average degree grows logarithmically in the size $n$ of the graph. In this weakly dense regime, we prove that the total variation distance to equilibrium displays a cutoff behaviour at the entropic time of order $\log(n)/\log\log(n)$. Moreover, we prove that on a precise window, the cutoff profile converges to the Gaussian tail function. This is qualitatively similar to what was proved in [6,7,8] for the directed configuration model, where degrees are deterministically fixed. In terms of statistical ensembles, our analysis provides an extension of these cutoff results from a hard to a soft-constrained model.
format Preprint
id arxiv_https___arxiv_org_abs_2402_15356
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mixing cutoff for simple random walks on the Chung-Lu digraph
Bianchi, Alessandra
Passuello, Giacomo
Probability
60J10, 05C80, 05C81
In this paper, we are interested in the mixing behaviour of simple random walks on inhomogeneous directed graphs. We focus our study on the Chung-Lu digraph, which is an inhomogeneous network that generalizes the Erdős-Rényi digraph. In particular, under the Chung-Lu model, edges are included in the graph independently and according to given Bernoulli laws, so that the average degrees are fixed. To guarantee the a.s. existence of a unique reversible measure, which is implied by the strong connectivity of the graph, we assume that the average degree grows logarithmically in the size $n$ of the graph. In this weakly dense regime, we prove that the total variation distance to equilibrium displays a cutoff behaviour at the entropic time of order $\log(n)/\log\log(n)$. Moreover, we prove that on a precise window, the cutoff profile converges to the Gaussian tail function. This is qualitatively similar to what was proved in [6,7,8] for the directed configuration model, where degrees are deterministically fixed. In terms of statistical ensembles, our analysis provides an extension of these cutoff results from a hard to a soft-constrained model.
title Mixing cutoff for simple random walks on the Chung-Lu digraph
topic Probability
60J10, 05C80, 05C81
url https://arxiv.org/abs/2402.15356