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The continuous time random walk (CTRW) approach has been widely applied to model large-scale non-Fickian transport in the flow through disordered media. Often, the underlying microscopic transport mechanisms and disorder characteristics are…

Fluid Dynamics · Physics 2024-03-12 Xiangnan Yu , Marco Dentz , HongGuang Sun , Yong Zhang

The continuous-time random walk (CTRW) model is useful for alleviating the computational burden of simulating diffusion in actual media. In principle, isotropic CTRW only requires knowledge of the step-size, $P_l$, and waiting-time, $P_t$,…

Statistical Mechanics · Physics 2017-01-19 Shahar Amitai , Raphael Blumenfeld

Continuous Time Random Walk models (CTRW) of anomalous diffusion are studied, where the anomalous exponent $\beta(x) \in (0,1)$ varies in space. This type of situation occurs e.g. in biophysics, where the density of the intracellular matrix…

Statistical Mechanics · Physics 2018-03-13 Peter Straka

Continuous time random walk (CTRW) subdiffusion along with the associated fractional Fokker-Planck equation (FFPE) is traditionally based on the premise of random clock with divergent mean period. This work considers an alternative CTRW and…

Statistical Mechanics · Physics 2014-09-24 Igor Goychuk

We propose a reaction-transport model for CTRW with non-linear reactions and non-exponential waiting time distributions. We derive non-linear evolution equation for mesoscopic density of particles. We apply this equation to the problem of…

Statistical Mechanics · Physics 2015-05-14 Sergei Fedotov

We consider a simple linear reversible isomerization reaction A <--> B under subdiffusion described by continuous time random walks (CTRW). The reactants' transformations take place independently on the motion and are described by constant…

Statistical Mechanics · Physics 2009-11-13 F. Sagues , V. P. Shkilev , I. M. Sokolov

We investigate the dynamics of a particle executing a general Continuous Time Random Walk (CTRW) in three dimensions under the influence of arbitrary time-varying external fields. Contrary to the general approach in recent works, our method…

Statistical Mechanics · Physics 2011-12-15 Shovan Dutta , Subhankar Ray , J. Shamanna

For the first time, the diffusion phase diagram in highly confined colloidal systems, predicted by Continuous Time Random Walk (CTRW), is experimentally obtained. Temporal and spatial fractional exponents, $\alpha$ and $\mu$, introduced…

Disordered Systems and Neural Networks · Physics 2015-05-27 M. Palombo , A. Gabrielli , S. De Santis , C. Cametti , G. Ruocco , S. Capuani

Anomalous diffusion processes, in particular superdiffusive ones, are known to be efficient strategies for searching and navigation by animals and also in human mobility. One way to create such regimes are L\'evy flights, where the walkers…

Physics and Society · Physics 2017-02-22 Sarah de Nigris , Timoteo Carletti , Renaud Lambiotte

The motion of self-propelled particles is modeled as a persistent random walk. An analytical framework is developed that allows the derivation of exact expressions for the time evolution of arbitrary moments of the persistent walk's…

Soft Condensed Matter · Physics 2015-07-28 Zeinab Sadjadi , M. Reza Shaebani , Heiko Rieger , Ludger Santen

We show the asymptotic long-time equivalence of a generic power law waiting time distribution to the Mittag-Leffler waiting time distribution, characteristic for a time fractional CTRW. This asymptotic equivalence is effected by a…

Statistical Mechanics · Physics 2008-05-18 Rudolf Gorenflo , Francesco Mainardi

Continuous-time random walk (CTRW) is a model of anomalous sub-diffusion in which particles are immobilized for random times between successive jumps. A power-law distribution of the waiting times, $\psi(\tau) \tau^{-(1+\alpha)}$, leads to…

Statistical Mechanics · Physics 2011-12-06 Shai Carmi , Eli Barkai

In this paper we study continuous time random walks (CTRWs) such that the holding time in each state has a distribution depending on the state itself. For such processes, we provide integro-differential (backward and forward) equations of…

Probability · Mathematics 2017-10-11 Costantino Ricciuti , Bruno Toaldo

We propose a new Directed Continuous-Time Random Walk (CTRW) model with memory. As CTRW trajectory consists of spatial jumps preceded by waiting times, in Directed CTRW, we consider the case with only positive spatial jumps. Moreover, we…

Statistical Finance · Quantitative Finance 2019-05-01 Jarosław Klamut , Tomasz Gubiec

We discuss large deviation properties of continuous-time random walks (CTRW) and present a general expression for the large deviation rate in CTRW in terms of the corresponding rates for the distributions of steps' lengths and waiting…

Statistical Mechanics · Physics 2021-04-14 Adrian Pacheco-Pozo , Igor M. Sokolov

We introduce a new class of asymmetric random walks on the one-dimensional infinite lattice. In this walk the direction of the jumps (positive or negative) is determined by a discrete-time renewal process which is independent of the jumps.…

Probability · Mathematics 2021-11-29 Thomas M. Michelitsch , Federico Polito , Alejandro P. Riascos

It is a well known fact that subdiffusion equations in terms of fractional derivatives can be obtained from Continuous Time Random Walk (CTRW) models with long-tailed waiting time distributions. Over the last years various authors have…

Biological Physics · Physics 2010-06-15 S. B. Yuste , E. Abad , K. Lindenberg

We introduce a model, in which a particle performs a continuous time random walk (CTRW) coupled to an environment with Ising dynamics. The particle shows locally varying diffusivity determined by the geometrical properties of the underlying…

Statistical Mechanics · Physics 2018-01-09 G. Muñoz-Gil , C. Charalambous , M. A. García-March , M. F. García-Parajo , C. Manzo , M. Lewenstein , A. Celi

Continuous Time Random Walks (CTRW) are widely used to coarse-grain the evolution of systems jumping from a metastable sub-set of their configuration space, or trap, to another via rare intermittent events. The multi-scaled behavior typical…

Statistical Mechanics · Physics 2014-01-21 Paolo Sibani

We analyze two models of subdiffusion with stochastic resetting. Each of them consists of two parts: subdiffusion based on the continuous-time random walk (CTRW) scheme and independent resetting events generated uniformly in time according…

Statistical Mechanics · Physics 2019-05-22 Łukasz Kuśmierz , Ewa Gudowska-Nowak