Marginals of the planar symmetric Markov random flight on long time intervals behave like the Goldstein-Kac telegraph process

Fuente: arXiv
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Main Author: Kolesnik, Alexander D.
Format: Preprint
Published: 2025
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author Kolesnik, Alexander D.
author_facet Kolesnik, Alexander D.
contents The planar symmetric Markov random flight $\bold X(t), \; t>0,$ is represented by the stochastic motion of a particle moving with constant finite speed $c>0$ in the Euclidean plane $\Bbb R^2$ and taking on its initial and each new directions at $λ$-Poisson ($λ>0$) distributed random time instants by choosing them at random according to the uniform distribution on the unit circumference. We consider the marginals of $\bold X(t)$, that is, the projection of this stochastic motion onto the axes. This projection onto the $x_1$-axis (respectively, onto the $x_2$-axis) represents a one-dimensional stochastic motion with random velocity $c \cosα$ (respectively, with random velocity $c \sinα$), where $α$ is a random variable distributed uniformly on the interval $[0, 2π)$. We prove that the density of the marginals of $\bold X(t)$ is asymptotically, as $t\to\infty$, equivalent to the density of the classical one-dimensional Goldstein-Kac telegraph process with parameters ($c, λ$). This unexpected and interesting result is confirmed by numerical calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2507_07525
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Marginals of the planar symmetric Markov random flight on long time intervals behave like the Goldstein-Kac telegraph process
Kolesnik, Alexander D.
Probability
60K35, 60J60, 62E20, 62F12, 82C41, 82C70
The planar symmetric Markov random flight $\bold X(t), \; t>0,$ is represented by the stochastic motion of a particle moving with constant finite speed $c>0$ in the Euclidean plane $\Bbb R^2$ and taking on its initial and each new directions at $λ$-Poisson ($λ>0$) distributed random time instants by choosing them at random according to the uniform distribution on the unit circumference. We consider the marginals of $\bold X(t)$, that is, the projection of this stochastic motion onto the axes. This projection onto the $x_1$-axis (respectively, onto the $x_2$-axis) represents a one-dimensional stochastic motion with random velocity $c \cosα$ (respectively, with random velocity $c \sinα$), where $α$ is a random variable distributed uniformly on the interval $[0, 2π)$. We prove that the density of the marginals of $\bold X(t)$ is asymptotically, as $t\to\infty$, equivalent to the density of the classical one-dimensional Goldstein-Kac telegraph process with parameters ($c, λ$). This unexpected and interesting result is confirmed by numerical calculations.
title Marginals of the planar symmetric Markov random flight on long time intervals behave like the Goldstein-Kac telegraph process
topic Probability
60K35, 60J60, 62E20, 62F12, 82C41, 82C70
url https://arxiv.org/abs/2507.07525