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Related papers: Continuity, the Bloch-Torrey equation, and Diffusi…

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The purpose of this tutorial is to introduce the main concepts behind normal and anomalous diffusion. Starting from simple, but well known experiments, a series of mathematical modeling tools are introduced, and the relation between them is…

Chaotic Dynamics · Physics 2008-05-06 Loukas Vlahos , Heinz Isliker , Yannis Kominis , Kyriakos Hizanidis

Diffusion probabilistic models (DPMs) which employ explicit likelihood characterization and a gradual sampling process to synthesize data, have gained increasing research interest. Despite their huge computational burdens due to the large…

Computer Vision and Pattern Recognition · Computer Science 2024-05-09 Yuheng Fan , Hanxi Liao , Shiqi Huang , Yimin Luo , Huazhu Fu , Haikun Qi

We develop a general analytical and numerical framework for estimating intra- and extra-neurite water fractions and diffusion coefficients, as well as neurite orientational dispersion, in each imaging voxel. By employing a set of rotational…

Biological Physics · Physics 2018-04-10 Dmitry S. Novikov , Jelle Veraart , Ileana O. Jelescu , Els Fieremans

A generalized continuum framework for the theory of solute transport in fluids is proposed and systematically developed. This framework rests on the introduction of a generic force balance for the solute, a balance distinct from the…

Soft Condensed Matter · Physics 2018-08-29 Eliot Fried , Shaun Sellers

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

The evolution of a large-scale poloidal magnetic field in accretion discs is an important problem because of its role in the launching of jets and winds and in determining the intensity of turbulence. In this paper, we develop a formalism…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Jerome Guilet , Gordon I. Ogilvie

Well-known Bloch equations describe the spin systems (electronic and nuclear) for any scale of time, from transient processes to steady states. Usually in solids T_2 << T_1. The question arises: what are the approximations that should be…

Other Condensed Matter · Physics 2010-06-08 M. D. Zviadadze , N. D. Chachava , A. G. Kvirikadze , A. K. Pokleba

Time evolution of the position-velocity correlation functions (PVCF) plays a key role in a new formalism of Brownian motion. A system of differential equations, which governs PVCF, is derived for magnetic Skyrmions on a 2-dimensional…

Statistical Mechanics · Physics 2019-07-17 E. Tamura , Y. Suzuki

The diffusion coefficient--a measure of dissipation, and the entropy--a measure of fluctuation are found to be intimately correlated in many physical systems. Unlike the fluctuation dissipation theorem in linear response theory, the…

Statistical Mechanics · Physics 2021-03-25 Yi Liao , Xiao-Bo Gong

Volume-filling cross-diffusion equations for the components of a tissue structure are formally derived from mass conservation laws and force balances for the interphase pressures and viscous drag forces in a multiphase approach. The…

Analysis of PDEs · Mathematics 2026-04-03 Ansgar Jüngel , Cordula Reisch , Sara Xhahysa

The distant dipolar field (DDF) is a long-range, nonlocal contribution to liquid-state spin dynamics that arises from intermolecular dipolar couplings and can generate multiple-quantum coherences and novel MRI contrast. Its sign-changing…

Other Condensed Matter · Physics 2026-04-07 Louis-S. Bouchard

Spin-current is an important physical quantity in present day spintronics and it might be very usefull in the physics of quantum plasma of spinning particles. Thus it is important to have an equation of the spin-current evolution. This…

Mesoscale and Nanoscale Physics · Physics 2015-04-10 P. A. Andreev , L. S. Kuz'menkov

Molecular diffusion measurements are widely used to probe microstructure in materials and living organisms noninvasively. The precise relation of diffusion metrics to microstructure remains a major challenge: In complex samples, it is often…

Biological Physics · Physics 2014-04-15 Dmitry S. Novikov , Els Fieremans , Jens H. Jensen , Joseph A. Helpern

A fundamental problem in plasma physics, space science, and astrophysics is the transport of energetic particles interacting with stochastic magnetic fields. In particular the motion of particles across a large scale magnetic field is…

Space Physics · Physics 2015-08-26 Andreas Shalchi

Using diffusion priors to solve inverse problems in imaging have significantly matured over the years. In this chapter, we review the various different approaches that were proposed over the years. We categorize the approaches into the more…

Machine Learning · Computer Science 2025-08-05 Hyungjin Chung , Jeongsol Kim , Jong Chul Ye

An overview of the author's papers on the new approach to the Brownian coagulation theory and its generalization to the diffusion-limited reaction rate theory is presented. The traditional diffusion approach of the Smoluchowski theory for…

Chemical Physics · Physics 2016-05-24 Mikhail S. Veshchunov

Diffusion Magnetic Resonance Imaging (dMRI) is an imaging technique with exquisite sensitivity to the microstructural properties of heterogeneous media. The conventionally adopted acquisition schemes involving single pulsed field gradients…

Biological Physics · Physics 2023-01-04 Deneb Boito , Cem Yolcu , Evren Özarslan

In this paper, we are interested in the collective friction of a cloud of particles on the viscous incompressible fluid in which they are moving. The particles velocities are assumed to be given and the fluid is assumed to be driven by the…

Analysis of PDEs · Mathematics 2024-09-12 Matthieu Hillairet , Ayman Moussa , Franck Sueur

A new theory for the dynamics of the magnetic particles and their magnetic moments in ferrofluids is developed. Based on a generalized Lagrangian formulation for the equations of motion of the colloidal particle, we introduce its…

Statistical Mechanics · Physics 2007-05-23 Claudio Scherer , Hans-Georg Matuttis

The Markovian diffusion theory in the phase space is generalized within the framework of the general theory of relativity. The introduction of moving orthonormal frame vectors both for the position as well the velocity space enables to…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Joachim Herrmann