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Continuous time random walks and Langevin equations are two classes of stochastic models for describing the dynamics of particles in the natural world. While some of the processes can be conveniently characterized by both of them, more…

Statistical Mechanics · Physics 2019-01-28 Xudong Wang , Yao Chen , Weihua Deng

In heterogeneous environments, the diffusivity is not constant but changes with time. It is important to detect changes in the diffusivity from single-particle-tracking trajectories in experiments. Here, we devise a novel method for…

Statistical Mechanics · Physics 2017-12-06 Takuma Akimoto , Eiji Yamamoto

The purpose of this paper is to provide new formulas for the estimation of the effective diffusion coefficient of an equation of Fick-Jacob's type obtained by projecting the two-dimensional diffusion equation along the normal direction of…

Mathematical Physics · Physics 2014-09-19 Carlos Valero Valdes , Rafael Herrera Guzman

A rigorous definition of a path integral for a spinning particle in three dimensions is given on a regular cubic lattice. The critical diffusion constant and the associated critical exponents in each spin are calculated. Continuum field…

High Energy Physics - Theory · Physics 2007-05-23 Masako Asano , Chigak Itoi , Shin-Ichi Kojima

Diffusion models are state-of-the-art methods in generative modeling when samples from a target probability distribution are available, and can be efficiently sampled, using score matching to estimate score vectors guiding a Langevin…

Machine Learning · Statistics 2024-06-21 Omar Chehab , Anna Korba

This paper is devoted to the hydrodynamic limit for the linear Boltzmann equation, in the case of a heavy tail equilibrium and a cross section which depends on the space variable and which degenerates for large velocities, without symmetry…

Analysis of PDEs · Mathematics 2025-03-13 Dahmane Dechicha

We explicitly solve the optimal switching problem for one-dimensional diffusions by directly employing the dynamic programming principle and the excessive characterization of the value function. The shape of the value function and the…

Optimization and Control · Mathematics 2009-05-25 Erhan Bayraktar , Masahiko Egami

Recent experimental results indicate that mixing is enhanced by a reciprocal flow induced inside a levitated droplet with an oscillatory deformation [T. Watanabe et al. Sci. Rep. 8, 10221 (2018)]. Generally, reciprocal flow cannot convect…

General dynamical transport of classical particles in disordered quasi-1D samples is viewed in the framework of scattering approach. Simple equation for the transfer-matrix is obtained within this unified picture. In the case of diffusive…

Condensed Matter · Physics 2008-02-03 Eugene Kogan

This work studies the parameter-dependent diffusion equation in a two-dimensional domain consisting of locally mirror symmetric layers. It is assumed that the diffusion coefficient is a constant in each layer. The goal is to find…

Numerical Analysis · Mathematics 2024-12-20 Antti Autio , Antti Hannukainen

The general, multidimensional barrier crossing problem for diffusive processes under the action of conservative forces is studied with the goal of developing tractable approximations. Particular attention is given to the effect of different…

Statistical Mechanics · Physics 2025-09-03 James F. Lutsko

The Langevin dynamics is a diffusion process extensively used, in particular in molecular dynamics simulations, to sample Gibbs measures. Some alternatives based on (piecewise deterministic) kinetic velocity jump processes have gained…

Numerical Analysis · Mathematics 2025-05-27 Nicolaï Gouraud , Lucas Journel , Pierre Monmarché

We consider the effective surface motion of a particle that freely diffuses in the bulk and intermittently binds to that surface. From an exact approach we derive various regimes of the effective surface motion characterized by physical…

Statistical Mechanics · Physics 2015-05-13 Aleksei V. Chechkin , Irwin M. Zaid , Michael A. Lomholt , Igor M. Sokolov , Ralf Metzler

Inspired by problems in biochemical kinetics, we study statistical properties of an overdamped Langevin process whose friction coefficient depends on the state of a similar, unobserved process. Integrating out the latter, we derive the long…

Statistical Mechanics · Physics 2009-08-13 Golan Bel , Ilya Nemenman

The self-diffusion process of a hard sphere fluid confined by two parallel plates separated by a distance on the order of the particle diameter is studied. The starting point is a closed kinetic equation for the distribution function that…

Statistical Mechanics · Physics 2025-10-24 Manuel Mayo , María Isabel García de Soria , Pablo Maynar , José Javier Brey

The use of the linear Boltzmann equation is proposed for transport in porous media in a column. By column experiments, we show that the breakthrough curve is reproduced by the linear Boltzmann equation. The advection-diffusion equation is…

Geophysics · Physics 2019-08-05 Kenji Amagai , Motoko Yamakawa , Manabu Machida , Yuko Hatano

The diffusion of a walk in the presence of traps is investigated. Different diffusion regimes are obtained considering the magnitude of the fluctuations in waiting times and jump distances. A constant velocity during the jump motion is…

Soft Condensed Matter · Physics 2015-06-25 Alexei Vazquez , Oscar Sotolongo Costa , Francois Brouers

In this paper, a certain type of linear boundary diffusion equation is studied. Such equation is crucial in the research of a non-linear boundary diffusion problem which was originated from the boundary heat control problem and Yamabe flow.…

Analysis of PDEs · Mathematics 2025-11-12 Xuzhou Yang

The generalized master equation with two times, introduced in earlier, applies to the problem of diffusion in an time-dependent (in general inhomogeneous) external field. We consider the case of the quasi Fokker-Planck approximation, when…

Soft Condensed Matter · Physics 2007-05-23 S. A. Trigger

We investigate a single particle on a 3-dimensional, cubic lattice with a random on-site potential (3D Anderson model). We concretely address the question whether or not the dynamics of the particle is in full accord with the diffusion…

Statistical Mechanics · Physics 2010-05-05 Robin Steinigeweg , Jochen Gemmer