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Main Author: Jettkant, Philipp
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2511.17486
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author Jettkant, Philipp
author_facet Jettkant, Philipp
contents We study the mean-field limit of the Atlas model and its connection to SDEs with dependence on the distribution of hitting and local times. The Atlas model describes a system of Brownian particles on the real line, where only the lowest ranked particle receives a positive drift, proportional to the number of particles. We show that in the mean-field limit the particle system converges to a novel SDE with reflection at a moving boundary, whose motion is such that the average local time spent at the boundary grows at a constant rate. In general, the boundary is represented by a measure, so the reflection must be interpreted in a relaxed sense. However, for sufficiently regular initial particle profiles, we prove that the boundary is a continuous function. Our analysis relies on a reformulation of the problem via McKean--Vlasov SDEs with interaction through hitting and local times.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17486
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Atlas Model and SDEs with Boundary Interaction
Jettkant, Philipp
Probability
We study the mean-field limit of the Atlas model and its connection to SDEs with dependence on the distribution of hitting and local times. The Atlas model describes a system of Brownian particles on the real line, where only the lowest ranked particle receives a positive drift, proportional to the number of particles. We show that in the mean-field limit the particle system converges to a novel SDE with reflection at a moving boundary, whose motion is such that the average local time spent at the boundary grows at a constant rate. In general, the boundary is represented by a measure, so the reflection must be interpreted in a relaxed sense. However, for sufficiently regular initial particle profiles, we prove that the boundary is a continuous function. Our analysis relies on a reformulation of the problem via McKean--Vlasov SDEs with interaction through hitting and local times.
title The Atlas Model and SDEs with Boundary Interaction
topic Probability
url https://arxiv.org/abs/2511.17486