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A self-propelled artificial microswimmer is often modeled as a ballistic Brownian particle moving with constant speed aligned along one of its axis, but changing direction due to random collisions with the environment. Similarly to thermal…

Soft Condensed Matter · Physics 2015-12-08 Pulak K. Ghosh , Yunyun Li , Giampiero Marchegiani , Fabio Marchesoni

The problem of diffusion in a porous medium with a spatially varying porosity is considered. The particular microstructure analyzed comprises a collection of impenetrable spheres, though the methods developed are general. Two different…

Fluid Dynamics · Physics 2017-10-12 Maria Bruna , S. Jonathan Chapman

We prove existence and uniqueness of a reaction-diffusion equation whose diffusivity is a non-linear functional of the boundary temperature. We do this by studying systems of one-dimensional reflecting diffusions whose noise is a function…

Probability · Mathematics 2021-07-29 Clayton Barnes

Although an intimate relation between entropy and diffusion has been advocated for many years and even seems to have been verified in theory and experiments, a quantitatively reliable study, and any derivation of an algebraic relation…

Statistical Mechanics · Physics 2020-07-22 Subhajit Acharya , Biman Bagchi

We consider the motion of a particle governed by a weakly random Hamiltonian flow. We identify temporal and spatial scales on which the particle trajectory converges to a spatial Brownian motion. The main technical issue in the proof is to…

Mathematical Physics · Physics 2009-11-11 T. Komorowski , L. Ryzhik

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

The constitutive quantities in Mori's theory, the residual forces, are expanded in terms of time dependent correlation functions and products of operators at $t=0$, where it is assumed that the time derivatives of the observables are given…

Statistical Mechanics · Physics 2015-06-25 G. Sauermann , H. Turschner , W. Just

An exact description of the statistical motion of active particles in three dimension is presented in the framework of a generalized diffusion equation. Such a generalization contemplates a non-local, in time and space, connecting (memory)…

Statistical Mechanics · Physics 2023-07-20 Francisco J Sevilla

Traditional theories of the NMR autocorrelation function for intramolecular dipole pairs assume single-exponential decay, yet the calculated autocorrelation of realistic systems display a rich, multi-exponential behavior resulting in…

The one-dimensional overdamped Brownian motion in a symmetric periodic potential modulated by external time-reversible noise is analyzed. The calculation of the effective diffusion coefficient is reduced to the mean first passage time…

Statistical Mechanics · Physics 2009-11-11 Bernardo Spagnolo , Alexander Dubkov

Diffusive molecular dynamics is a novel model for materials with atomistic resolution that can reach diffusive time scales. The main ideas of diffusive molecular dynamics are to first minimize an approximate variational Gaussian free energy…

Numerical Analysis · Mathematics 2015-06-09 Gideon Simpson , Mitchell Luskin , David J. Srolovitz

The transport equation of active motion is generalised to consider time-fractional dynamics for describing the anomalous diffusion of self-propelled particles observed in many different systems. In the present study, we consider an…

Statistical Mechanics · Physics 2023-10-27 Francisco J. Sevilla , Guillermo Chacón-Acosta , Trifce Sandev

We introduce and analyze a model for the transport of particles or energy in extended lattice systems. The dynamics of the model acts on a discrete phase space at discrete times but has nonetheless some of the characteristic properties of…

Mathematical Physics · Physics 2015-06-12 Raphael Lefevere

The ability to efficiently and accurately calculate equilibrium time correlation functions of many-body condensed phase quantum systems is one of the outstanding problems in theoretical chemistry. The Nakajima-Zwanzig-Mori formalism coupled…

Chemical Physics · Physics 2017-04-05 Andrés Montoya-Castillo , David R. Reichman

Diffusion models have transformed image synthesis through iterative denoising, by defining trajectories from noise to coherent data. While their capabilities are widely celebrated, a critical challenge remains unaddressed: ensuring…

Computer Vision and Pattern Recognition · Computer Science 2025-12-22 Andreas Floros , Seyed-Mohsen Moosavi-Dezfooli , Pier Luigi Dragotti

Diffusion Transformer, the backbone of Sora for video generation, successfully scales the capacity of diffusion models, pioneering new avenues for high-fidelity sequential data generation. Unlike static data such as images, sequential data…

Machine Learning · Computer Science 2025-02-05 Hengyu Fu , Zehao Dou , Jiawei Guo , Mengdi Wang , Minshuo Chen

In the first paper of this series, I investigated whether a wavefunction model of a heavy particle and a collection of light particles might generate "Brownian-Motion-Like" trajectories of the heavy particle. I concluded that it was…

Quantum Physics · Physics 2023-08-04 W. David Wick

Recent works have reported on the collective behavior of multiphase systems under fractional flow. Such behavior has been linked to pressure and/or flux fluctuations under stationary flow conditions that occur over a broad range of…

Fluid Dynamics · Physics 2025-02-18 Dick Bedeaux , Signe Kjelstrup , Steffen Berg , Umar Alfazazi , Ryan T. Armstrong

Lateral diffusion of molecules on surfaces plays a very important role in various biological processes, including lipid transport across the cell membrane, synaptic transmission and other phenomena such as exo- and endocytosis, signal…

Analysis of PDEs · Mathematics 2013-11-12 A. B. Duncan , C. M. Elliott , G. A. Pavliotis , A. M. Stuart

Of primary interest in this paper is the numerical approximation of a time dependent fractional, in space, diffusion equation where the domain is assumed to be nonhomogeneous, having different axial diffusion coefficients. This work is…

Numerical Analysis · Mathematics 2026-05-12 T. Catoe , V. J. Ervin