The number of minima in random landscapes generated by constrained random walk and Lévy flights: universal properties

Fuente: arXiv
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Hauptverfasser: Kundu, Anupam, Majumdar, Satya N., Schehr, Gregory
Format: Preprint
Veröffentlicht: 2024
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author Kundu, Anupam
Majumdar, Satya N.
Schehr, Gregory
author_facet Kundu, Anupam
Majumdar, Satya N.
Schehr, Gregory
contents We provide a uniform framework to compute the exact distribution of the number of minima/maxima in three different random walk landscape models in one dimension. The landscape is generated by the trajectory of a discrete-time continuous space random walk with arbitrary symmetric and continuous jump distribution at each step. In model I, we consider a ``free'' random walk of $N$ steps. In model II, we consider a ``meander landscape'' where the random walk, starting at the origin, stays non-negative up to $N$ steps. In model III, we study a ``first-passage landscape'' which is generated by the trajectory of a random walk that starts at the origin and stops when it crosses the origin for the first time. We demonstrate that while the exact distribution of the number of minima is different in the three models, for each model it is universal for all $N$, in the sense that it does not depend on the jump distribution as long as it is symmetric and continuous. In the last two cases we show that this universality follows from a non trivial mapping to the Sparre Andersen theorem known for the first-passage probability of discrete-time random walks with symmetric and continuous jump distribution. Our analytical results are in excellent agreement with our numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2409_12906
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The number of minima in random landscapes generated by constrained random walk and Lévy flights: universal properties
Kundu, Anupam
Majumdar, Satya N.
Schehr, Gregory
Statistical Mechanics
Mathematical Physics
Probability
We provide a uniform framework to compute the exact distribution of the number of minima/maxima in three different random walk landscape models in one dimension. The landscape is generated by the trajectory of a discrete-time continuous space random walk with arbitrary symmetric and continuous jump distribution at each step. In model I, we consider a ``free'' random walk of $N$ steps. In model II, we consider a ``meander landscape'' where the random walk, starting at the origin, stays non-negative up to $N$ steps. In model III, we study a ``first-passage landscape'' which is generated by the trajectory of a random walk that starts at the origin and stops when it crosses the origin for the first time. We demonstrate that while the exact distribution of the number of minima is different in the three models, for each model it is universal for all $N$, in the sense that it does not depend on the jump distribution as long as it is symmetric and continuous. In the last two cases we show that this universality follows from a non trivial mapping to the Sparre Andersen theorem known for the first-passage probability of discrete-time random walks with symmetric and continuous jump distribution. Our analytical results are in excellent agreement with our numerical simulations.
title The number of minima in random landscapes generated by constrained random walk and Lévy flights: universal properties
topic Statistical Mechanics
Mathematical Physics
Probability
url https://arxiv.org/abs/2409.12906