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We use direct numerical simulations to compute turbulent transport coefficients for passive scalars in turbulent rotating flows. Effective diffusion coefficients in the directions parallel and perpendicular to the rotations axis are…

Fluid Dynamics · Physics 2013-02-13 P. Rodriguez Imazio , P. D. Mininni

It is well known that on long time scales the behaviour of tracer particles diffusing in a cellular flow is effectively that of a Brownian motion. This paper studies the behaviour on "intermediate" time scales before diffusion sets in.…

Analysis of PDEs · Mathematics 2016-09-09 Gautam Iyer , Alexei Novikov

We propose a variety of models of random walk, discrete in space and time, suitable for simulating stable random variables of arbitrary index $\alpha$ ($0< \alpha \le 2$), in the symmetric case. We show that by properly scaled transition to…

Statistical Mechanics · Physics 2009-10-31 Rudolf Gorenflo , Gianni De Fabritiis , Francesco Mainardi

We model two time and space scales discrete observations by using a unique continuous diffusion process with time dependent coefficient. We define new parameters for the large scale model as functions of the small scale distribution…

Methodology · Statistics 2009-09-09 V. Calian , G. Stefansson , L. P. Folkow , A. S. Blix

We consider random walks in dynamic random environments given by Markovian dynamics on $\mathbb{Z}^d$. We assume that the environment has a stationary distribution $\mu$ and satisfies the Poincar\'e inequality w.r.t. $\mu$. The random walk…

Probability · Mathematics 2016-11-01 L. Avena , O. Blondel , A. Faggionato

In this paper we develop a random walk model on lattice for coordinate dependent diffusion at constant temperature in contact with a heat bath. We employ here a coordinate dependent waiting time of the random walker to make the diffusivity…

Statistical Mechanics · Physics 2020-08-27 Rohan Maniar , A. Bhattacharyay

Random walks are ubiquitous in the sciences, and they are interesting from both theoretical and practical perspectives. They are one of the most fundamental types of stochastic processes; can be used to model numerous phenomena, including…

Physics and Society · Physics 2020-04-13 Naoki Masuda , Mason A. Porter , Renaud Lambiotte

We find a general formula for the distribution of time-averaged observables for systems modeled according to the sub-diffusive continuous time random walk. For Gaussian random walks coupled to a thermal bath we recover ergodicity and…

Statistical Mechanics · Physics 2009-11-13 Adi Rebenshtok , Eli Barkai

We introduce a general model of trapping for random walks on graphs. We give the possible scaling limits of these Randomly Trapped Random Walks on $\mathbb {Z}$. These scaling limits include the well-known fractional kinetics process, the…

Probability · Mathematics 2015-10-30 Gérard Ben Arous , Manuel Cabezas , Jiří Černý , Roman Royfman

For normally reflected Brownian motion and for simple random walk on independently growing in time d-dimensional domains, d>=3, we establish a sharp criterion for recurrence versus transience in terms of the growth rate.

Probability · Mathematics 2014-08-28 Amir Dembo , Ruojun Huang , Vladas Sidoravicius

Linear diffusions are used to model a large number of stochastic processes in physics, including small mechanical and electrical systems perturbed by thermal noise, as well as Brownian particles controlled by electrical and optical forces.…

Statistical Mechanics · Physics 2023-05-10 Johan du Buisson , Hugo Touchette

We consider a continuous-time random walk in the quarter plane for which the transition intensities are constant on each of the four faces $(0,\infty)^2$, $F_1=\{0\}\times(0,\infty)$, $F_2=(0,\infty)\times\{0\}$ and $\{(0,0)\}$. We show…

Probability · Mathematics 2024-03-04 Rami Atar , Amarjit Budhiraja

Recent large deviation results have provided general lower bounds for the fluctuations of time-integrated currents in the steady state of stochastic systems. A corollary are so-called thermodynamic uncertainty relations connecting precision…

Statistical Mechanics · Physics 2017-03-29 Juan P. Garrahan

We analyse how simple local constraints in two dimensions lead a defect to exhibit robust, non-transient, and tunable, subdiffusion. We uncover a rich dynamical phenomenology realised in ice- and dimer-type models. On the microscopic scale…

Mesoscale and Nanoscale Physics · Physics 2025-04-02 Nilotpal Chakraborty , Markus Heyl , Roderich Moessner

We introduce a variation of the step-reinforced random walk with general memory. For the diffusive regime, we establish a functional invariance principle and show that, given suitable conditions on the memory sequence, the arising limiting…

Probability · Mathematics 2024-02-15 Marco Bertenghi , Lucile Laulin

Brownian motion in terms of Lifson and Jackson (LJ) formula has been widely explored in periodic systems and it has been believed for a long time that the LJ formula only applies to periodic potentials. Recently we show that for the…

Statistical Mechanics · Physics 2025-10-14 Ming Gong

The versatility of renewal theory is owed to its abstract formulation. Renewals can be interpreted as steps of a random walk, switching events in two-state models, domain crossings of a random motion, etc. We here discuss a renewal process…

Statistical Mechanics · Physics 2014-03-03 Johannes H. P. Schulz , Eli Barkai , Ralf Metzler

We consider reversible random walks in random environment obtained from symmetric long--range jump rates on a random point process. We prove almost sure transience and recurrence results under suitable assumptions on the point process and…

Probability · Mathematics 2015-11-30 P. Caputo , A. Faggionato , A. Gaudilliere

In this paper, we consider random walk in random environment on $\mathbb{Z}^{d}\,(d\geq1)$ and prove the Strassen's strong invariance principle for this model, via martingale argument and the theory of fractional coboundaries of Derriennic…

Probability · Mathematics 2010-04-20 Guangyu Yang , Yu Miao , Dihe Hu

Asymptotic theory for approximate martingale estimating functions is generalised to diffusions with finite-activity jumps, when the sampling frequency and terminal sampling time go to infinity. Rate optimality and efficiency are of…

Methodology · Statistics 2018-09-05 Nina Munkholt Jakobsen , Michael Sørensen