Recurrence, transience and anti-concentration of Rademacher random walks

Fuente: arXiv
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Main Authors: Bhattacharya, Satyaki, Crane, Edward, Johnston, Tom
Format: Preprint
Published: 2025
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author Bhattacharya, Satyaki
Crane, Edward
Johnston, Tom
author_facet Bhattacharya, Satyaki
Crane, Edward
Johnston, Tom
contents The Rademacher random walk associated with a deterministic sequence $(a_n)_{n \geq 1}$ is the walk which starts at zero and, at step $i$, independently steps either up or down by $a_i$ with equal probability. We continue the study begun by Bhattacharya and Volkov in 2023 of the transience or recurrence of one-dimensional Rademacher random walks. In particular, we show that if the sequence of step sizes is bounded, the walk is weakly recurrent, meaning that it returns infinitely often to a random finite interval, while if the step sizes tend to infinity arbitrarily slowly, the walk may be transient. On the other hand, using a construction with integer step sizes, we show that the step sizes may grow arbitrarily fast and still give a weakly recurrent random walk. We also show, using a construction with non-integer step sizes, that the same conclusion holds even if we restrict to strictly increasing step sizes. However, we prove that if $a_n = n^{α+ o(1)}$ for some $α> 1/2$, then the walk is transient. We show that the bound on $α$ is tight by giving an example where $a_n = Θ(n^{1/2})$ and the walk is weakly recurrent.
format Preprint
id arxiv_https___arxiv_org_abs_2510_24568
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Recurrence, transience and anti-concentration of Rademacher random walks
Bhattacharya, Satyaki
Crane, Edward
Johnston, Tom
Probability
The Rademacher random walk associated with a deterministic sequence $(a_n)_{n \geq 1}$ is the walk which starts at zero and, at step $i$, independently steps either up or down by $a_i$ with equal probability. We continue the study begun by Bhattacharya and Volkov in 2023 of the transience or recurrence of one-dimensional Rademacher random walks. In particular, we show that if the sequence of step sizes is bounded, the walk is weakly recurrent, meaning that it returns infinitely often to a random finite interval, while if the step sizes tend to infinity arbitrarily slowly, the walk may be transient. On the other hand, using a construction with integer step sizes, we show that the step sizes may grow arbitrarily fast and still give a weakly recurrent random walk. We also show, using a construction with non-integer step sizes, that the same conclusion holds even if we restrict to strictly increasing step sizes. However, we prove that if $a_n = n^{α+ o(1)}$ for some $α> 1/2$, then the walk is transient. We show that the bound on $α$ is tight by giving an example where $a_n = Θ(n^{1/2})$ and the walk is weakly recurrent.
title Recurrence, transience and anti-concentration of Rademacher random walks
topic Probability
url https://arxiv.org/abs/2510.24568