Large deviations of slow-fast systems driven by fractional Brownian motion

Fuente: arXiv
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Autori principali: Gailus, Siragan, Gasteratos, Ioannis
Natura: Preprint
Pubblicazione: 2022
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author Gailus, Siragan
Gasteratos, Ioannis
author_facet Gailus, Siragan
Gasteratos, Ioannis
contents We consider a multiscale system of stochastic differential equations in which the slow component is perturbed by a small fractional Brownian motion with Hurst index $H>1/2$ and the fast component is driven by an independent Brownian motion. Working in the framework of Young integration, we use tools from fractional calculus and weak convergence arguments to establish a Large Deviation Principle in the homogenized limit, as the noise intensity and time-scale separation parameters vanish at an appropriate rate. Our approach is based in the study of the limiting behavior of an associated controlled system. We show that, in certain cases, the non-local rate function admits an explicit non-variational form. The latter allows us to draw comparisons to the case $H=1/2$ which corresponds to the classical Freidlin-Wentzell theory. Moreover, we study the asymptotics of the rate function as $H\rightarrow{1/2}^+$ and show that it is discontinuous at $H=1/2.$
format Preprint
id arxiv_https___arxiv_org_abs_2210_03678
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Large deviations of slow-fast systems driven by fractional Brownian motion
Gailus, Siragan
Gasteratos, Ioannis
Probability
60F10, 60G22, 60H10, 93E20
We consider a multiscale system of stochastic differential equations in which the slow component is perturbed by a small fractional Brownian motion with Hurst index $H>1/2$ and the fast component is driven by an independent Brownian motion. Working in the framework of Young integration, we use tools from fractional calculus and weak convergence arguments to establish a Large Deviation Principle in the homogenized limit, as the noise intensity and time-scale separation parameters vanish at an appropriate rate. Our approach is based in the study of the limiting behavior of an associated controlled system. We show that, in certain cases, the non-local rate function admits an explicit non-variational form. The latter allows us to draw comparisons to the case $H=1/2$ which corresponds to the classical Freidlin-Wentzell theory. Moreover, we study the asymptotics of the rate function as $H\rightarrow{1/2}^+$ and show that it is discontinuous at $H=1/2.$
title Large deviations of slow-fast systems driven by fractional Brownian motion
topic Probability
60F10, 60G22, 60H10, 93E20
url https://arxiv.org/abs/2210.03678