Fast rare events in exit times distributions of jump processes

Fuente: arXiv
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Main Authors: Vezzani, Alessandro, Burioni, Raffaella
Format: Preprint
Published: 2023
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author Vezzani, Alessandro
Burioni, Raffaella
author_facet Vezzani, Alessandro
Burioni, Raffaella
contents Rare events in the first-passage distributions of jump processes are capable of triggering anomalous reactions or series of events. Estimating their probability is particularly important when the jump probabilities have broad-tailed distributions, and rare events are therefore not so rare. We formulate a general approach for estimating the contribution of fast rare events to the exit probabilities in the presence of fat tailed distributions. Using this approach, we study three jump processes that are used to model a wide class of phenomena ranging from biology to transport in disordered systems, ecology and finance: discrete time random-walks, Lévy walks and the Lévy-Lorentz gas. We determine the exact form of the scaling function for the probability distribution of fast rare events, in which the jump process exits from an interval in a very short time at a large distance opposite to the starting point. In particular, we show that events occurring on time scales orders of magnitude smaller than the typical time scale of the process can make a significant contribution to the exit probability. Our results are confirmed by extensive numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2309_16227
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Fast rare events in exit times distributions of jump processes
Vezzani, Alessandro
Burioni, Raffaella
Statistical Mechanics
Rare events in the first-passage distributions of jump processes are capable of triggering anomalous reactions or series of events. Estimating their probability is particularly important when the jump probabilities have broad-tailed distributions, and rare events are therefore not so rare. We formulate a general approach for estimating the contribution of fast rare events to the exit probabilities in the presence of fat tailed distributions. Using this approach, we study three jump processes that are used to model a wide class of phenomena ranging from biology to transport in disordered systems, ecology and finance: discrete time random-walks, Lévy walks and the Lévy-Lorentz gas. We determine the exact form of the scaling function for the probability distribution of fast rare events, in which the jump process exits from an interval in a very short time at a large distance opposite to the starting point. In particular, we show that events occurring on time scales orders of magnitude smaller than the typical time scale of the process can make a significant contribution to the exit probability. Our results are confirmed by extensive numerical simulations.
title Fast rare events in exit times distributions of jump processes
topic Statistical Mechanics
url https://arxiv.org/abs/2309.16227