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Mathematical models of motility are often based on random-walk descriptions of discrete individuals that can move according to certain rules. It is usually the case that large masses concentrated in small regions of space have a great…

Physics and Society · Physics 2022-11-23 Carles Falcó

Computational modelling of diffusion in heterogeneous media is prohibitively expensive for problems with fine-scale heterogeneities. A common strategy for resolving this issue is to decompose the domain into a number of non-overlapping…

Computational Physics · Physics 2021-08-26 Nathan G. March , Elliot J. Carr , Ian W. Turner

This article concerns a systemic manifestation of small scale interfacial heterogeneities in large scale quantities of interest to a variety of diverse applications spanning the earth, biological and ecological sciences. Beginning with…

Statistics Theory · Mathematics 2013-12-24 Jorge M. Ramirez , Enrique A. Thomann , Edward C. Waymire

Various biological cells secrete diffusing chemical compounds into their environment for communication purposes. Secretion usually takes place over the cell membrane in a spatially heterogeneous manner. Mathematical models of these…

Numerical Analysis · Mathematics 2025-11-20 Qiyao Peng , Sander C. Hille

Reaction-diffusion models with nonlocal constraints naturally arise as limiting cases of coupled bulk-surface models of intracellular signalling. In this paper, a minimal, mass-conserving model of cell-polarization on a curved membrane is…

Pattern Formation and Solitons · Physics 2022-10-04 Pearson W. Miller , Daniel Fortunato , Matteo Novaga , Stanislav Y. Shvartsman , Cyrill B. Muratov

The molecular motion in heterogeneous media displays anomalous diffusion by the mean-squared displacement $\langle X^2(t) \rangle = 2 D t^\alpha$. Motivated by experiments reporting populations of the anomalous diffusion parameters $\alpha$…

Biological Physics · Physics 2025-10-09 Yann Lanoiselée , Gianni Pagnini , Agnieszka Wyłomańska

On long enough timescales, chaotic diffusion has the potential to significantly alter the appearance of a dynamical system. The solar system is no exception: diffusive processes take part in the transportation of small bodies and provide…

Earth and Planetary Astrophysics · Physics 2023-06-14 Emese Kővári , Emese Forgács-Dajka , Tamás Kovács , Csaba Kiss , Zsolt Sándor

Using the methods of computer modeling this scientific paper studies the special features of diffusion of the particles subjected to the external periodic force in the crystal lattice. The particle motion is described by a Langevin…

Statistical Mechanics · Physics 2011-11-04 I. G. Marchenko , I. I. Marchenko

In this paper, we argue that iterative computation with diffusion models offers a powerful paradigm for not only generation but also visual perception tasks. We unify tasks such as depth estimation, optical flow, and amodal segmentation…

Computer Vision and Pattern Recognition · Computer Science 2024-11-19 Rahul Ravishankar , Zeeshan Patel , Jathushan Rajasegaran , Jitendra Malik

Light diffusion is usually associated with thick, opaque media. Indeed, multiple scattering is necessary for the onset of the diffusive regime and such condition is generally not met in almost transparent media. Nonetheless, at long enough…

Diffusion is a fundamental physical phenomenon with critical applications in fields such as metallurgy, cell biology, and population dynamics. While standard diffusion is well-understood, anomalous diffusion often requires complex non-local…

Statistical Mechanics · Physics 2026-01-16 Gabriel Barreiro , Vladimir Pérez-Veloz

We study the mass-conserved reaction-diffusion system known as the wave-pinning model, which serves as a minimal framework for describing cell polarity. In this model, the interplay between reaction kinetics and slow diffusion forms a sharp…

Dynamical Systems · Mathematics 2026-01-09 Shunsuke Kobayashi , Koya Sakakibara , Taikei Uechi

We consider the time dependent dispersion properties of overdamped tracer particles diffusing in a one dimensional periodic potential under the influence of an additional constant tilting force $F$. The system is studied in the region where…

Statistical Mechanics · Physics 2017-02-01 T. Guérin , D. S. Dean

Abstract. The present work considers a change in the momentum under the transfer of a solution through the interface. It is shown that pressure related to the partial volumes of components arises in a solution under diffusion. As a result,…

Statistical Mechanics · Physics 2021-02-16 Alex Guskov

Intracrystalline diffusion is an invaluable tool for estimating timescales of geological events. Diffusion is typically modeled using gradients in chemical potential. However, chemical potential is derived for uniform pressure and…

Materials Science · Physics 2023-06-22 Benjamin L. Hess , Jay J. Ague

This paper considers a time-fractional diffusion-wave equation with a high-contrast heterogeneous diffusion coefficient. A numerical solution to this problem can present great computational challenges due to its multiscale nature.…

Numerical Analysis · Mathematics 2025-02-14 Huiran Bai , Dmitry Ammosov , Yin Yang , Wei Xie , Mohammed Al Kobaisi

Diffusion of particles through an heterogenous obstacle line is modeled as a two-dimensional diffusion problem with a one--directional nonlinear convective drift and is examined using two-scale asymptotic analysis. At the scale where the…

Analysis of PDEs · Mathematics 2018-04-24 Emilio N. M. Cirillo , Ida de Bonis , Adrian Muntean , Omar Richardson

We present analytical results for the biased diffusion of particles moving under a constant force in a randomly layered medium. The influence of this medium on the particle dynamics is modeled by a piecewise constant random force. The…

Statistical Mechanics · Physics 2010-02-10 S. I. Denisov , H. Kantz

This paper studies the mechanisms of dispersion in the laminar flow through the pore space of a $3$-dimensional porous medium. We focus on pre-asymptotic transport prior to the asymptotic hydrodynamic dispersion regime, in which solute…

Fluid Dynamics · Physics 2018-03-05 Marco Dentz , Matteo Icardi , Juan J. Hidalgo

Anomalous diffusion, process in which the mean-squared displacement of system states is a non-linear function of time, is usually identified in real stochastic processes by comparing experimental and theoretical displacements at relatively…

Data Analysis, Statistics and Probability · Physics 2013-05-29 Serge F. Timashev , Yuriy S. Polyakov , Pavel I. Misurkin , Sergey G. Lakeev