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Main Authors: Banerjee, Sayan, Budhiraja, Amarjit, Imon, Dilshad
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2404.13117
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author Banerjee, Sayan
Budhiraja, Amarjit
Imon, Dilshad
author_facet Banerjee, Sayan
Budhiraja, Amarjit
Imon, Dilshad
contents We study a model for flocking given by a $n$-particle system under which each particle jumps forward by a random amount, independently sampled from a given distribution $θ$, with rate given by a non-increasing function $w$ of its signed distance from the system center of mass. This model was introduced in Balázs et. al. (2014) and some of its properties were studied for the case when $w$ is bounded. In the current work we are interested in the setting where $w$ is unbounded, and this feature results in a stochastic dynamical system for interacting particles with fast and large jumps for which little is available in the literature. We characterize the large $n$ limit (the so-called `fluid limit') of the empirical measure process associated with the system and prove a propagation of chaos result. Next, for the centered $n$-particle system, by constructing suitable Lyapunov functions, we establish existence and uniqueness of stationary distributions and study their tail properties. In the special case where $w$ is an exponential function and $θ$ is an exponential distribution, by establishing that all stationary solutions of the McKean-Vlasov equation must be the unique fixed point of the equation, we prove a propagation of chaos result at $t=\infty$ and establish convergence of the particle system, starting from stationarity, in the large $n$ limit, to a traveling wave solution of the McKean-Vlasov equation. The proof of this result may be of interest for other interacting particle systems where convexity properties or functional inequalities generally used for establishing such a result are not available. Our work answers several open problems posed in Balázs et. al.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13117
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Flocking under Fast and Large Jumps: Stability, Chaos, and Traveling Waves
Banerjee, Sayan
Budhiraja, Amarjit
Imon, Dilshad
Probability
We study a model for flocking given by a $n$-particle system under which each particle jumps forward by a random amount, independently sampled from a given distribution $θ$, with rate given by a non-increasing function $w$ of its signed distance from the system center of mass. This model was introduced in Balázs et. al. (2014) and some of its properties were studied for the case when $w$ is bounded. In the current work we are interested in the setting where $w$ is unbounded, and this feature results in a stochastic dynamical system for interacting particles with fast and large jumps for which little is available in the literature. We characterize the large $n$ limit (the so-called `fluid limit') of the empirical measure process associated with the system and prove a propagation of chaos result. Next, for the centered $n$-particle system, by constructing suitable Lyapunov functions, we establish existence and uniqueness of stationary distributions and study their tail properties. In the special case where $w$ is an exponential function and $θ$ is an exponential distribution, by establishing that all stationary solutions of the McKean-Vlasov equation must be the unique fixed point of the equation, we prove a propagation of chaos result at $t=\infty$ and establish convergence of the particle system, starting from stationarity, in the large $n$ limit, to a traveling wave solution of the McKean-Vlasov equation. The proof of this result may be of interest for other interacting particle systems where convexity properties or functional inequalities generally used for establishing such a result are not available. Our work answers several open problems posed in Balázs et. al.
title Flocking under Fast and Large Jumps: Stability, Chaos, and Traveling Waves
topic Probability
url https://arxiv.org/abs/2404.13117