Area under subdiffusive random walks

TL;DR

This paper analyzes the statistical properties of the area and absolute area under subdiffusive random walk trajectories across various models, providing theoretical insights supported by simulations.

Contribution

It introduces a unified framework to compute moments and probability densities of areas in different subdiffusion models, highlighting their differences and experimental relevance.

Findings

Derived moments and scaling laws for area functionals

Identified differences between area and absolute area statistics

Validated theoretical results with Monte Carlo simulations

Abstract

We study the statistical properties of the area and the absolute area under the trajectories of subdiffusive random walks. Using different frameworks to describe subdiffusion (as the scaled Brownian motion, fractional Brownian motion, the continuous-time random walk or the Brownian motion in heterogeneous media), we compute the first two moments, the ergodicity breaking parameter for the absolute area and infer a general scaling for the probability density functions of these functionals. We discuss the differences between the statistical properties of the area and the absolute area for the different subdiffusion models and illustrate the experimental interest of our results. Our theoretical findings are supported by Monte Carlo simulations showing an excellent agreement.