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A finite difference numerical method is investigated for fractional order diffusion problems in one space dimension. For this, a mathematical model is developed to incorporate homogeneous Dirichlet and Neumann type boundary conditions. The…

Numerical Analysis · Mathematics 2014-11-07 Béla J. Szekeres , Ferenc Izsák

We study the unique continuation property for the neutron transport equation and for a simplified model of the Fokker-Planck equation in a bounded domain with absorbing boundary condition. An observation estimate is derived. It depends on…

Analysis of PDEs · Mathematics 2016-05-09 Claude Bardos , Kim Dang Phung

We give simple proofs of hypoelliptic estimates for some models of kinetic equations with a fractional order diffusion part. The proofs are based on energy estimates together with F. Bouchut and B. Perthame previous ideas.

Analysis of PDEs · Mathematics 2011-02-14 Radjesvarane Alexandre

A fluid-dynamic approach to the diffusion of heavy quarks in the quark--gluon plasma (QGP) is presented. Specifically, we analyze the Fokker-Planck equation for the momentum transport of heavy quarks from a fluid perspective and use a…

Nuclear Theory · Physics 2022-08-31 F. Capellino , A. Beraudo , A. Dubla , S. Floerchinger , S. Masciocchi , J. Pawlowski , I. Selyuzhenkov

The emergence of various notions of ``consistency'' in diffusion models has garnered considerable attention and helped achieve improved sample quality, likelihood estimation, and accelerated sampling. Although similar concepts have been…

Machine Learning · Computer Science 2023-08-02 Chieh-Hsin Lai , Yuhta Takida , Toshimitsu Uesaka , Naoki Murata , Yuki Mitsufuji , Stefano Ermon

In recent years, several fractional generalizations of the usual Kramers-Fokker-Planck equation have been presented. Using an idea of Fogedby [H.C. Fogedby, Phys. Rev. E {\bf 50}, 041103 (1994), we show how these equations are related to…

Statistical Mechanics · Physics 2007-05-23 R. Friedrich , S. Eule , F. Jenko

We study the existence and the uniqueness of a solution $\fy$ to the linear Fokker-Planck equation $-\Delta \fy + \div(\fy \F) = f$ in a bounded domain of $\R^d$ when $\F$ is a "confinement" vector field acting for instance like the inverse…

Classical Analysis and ODEs · Mathematics 2009-04-20 Laurent Chupin

We present equations of motion for charged particles using balanced equations, and without introducing explicitly divergent quantities. This derivation contains as particular cases some well known equations of motion, as the Lorentz-Dirac…

General Relativity and Quantum Cosmology · Physics 2012-03-08 Emanuel Gallo , Osvaldo M. Moreschi

We present a model of diffusion in heterogeneous environment, which qualitatively reflects the transport properties of a polymeric membrane with carbon nanotubes. We derived Fokker-Planck equation from system of stochastic equations,…

Materials Science · Physics 2020-08-19 Ilia Kalashnikov , Polina Likhomanova

Fractional diffusion equations for three-dimensional lattice models based on fractional-order differences of the Grunwald-Letnikov type are suggested. These lattice fractional diffusion equations contain difference operators that describe…

Statistical Mechanics · Physics 2015-03-13 Vasily E. Tarasov

The temporal Fokker-Plank equation [{\it J. Stat. Phys.}, {\bf 3/4}, 527 (2003)] or propagation-dispersion equation was derived to describe diffusive processes with temporal dispersion rather than spatial dispersion as in classical…

Statistical Mechanics · Physics 2016-02-01 Jean Pierre Boon , James F. Lutsko

We study an initial-boundary value problem of variable-order time-fractional diffusion equations in one space dimension. Based on the wellposedness of the proposed model and the smoothing properties of its solutions, which are shown to be…

Analysis of PDEs · Mathematics 2020-01-08 Xiangcheng Zheng , Jin Cheng , Hong Wang

A self-consistent and universal description of friction and diffusion for Brownian particles (grains) in different systems, as a gas with Boltzmann collisions, dusty plasma with ion absorption by grains, and for active particles (e.g.,…

Statistical Mechanics · Physics 2009-11-10 S. A. Trigger , G. J. F. van Heijst , P. P. J. M. Schram

We develop a general framework for response theory in diffusion processes governed by Fokker-Planck equations, based on the notion of the Dissipation Function. Using the analytically solvable Brownian oscillator model, we derive exact…

Statistical Mechanics · Physics 2025-07-25 Matteo Colangeli , Lamberto Rondoni , Pasquale Vozza

Microscopic theory of Brownian motion of a particle of mass $M$ in a bath of molecules of mass $m\ll M$ is considered beyond lowest order in the mass ratio $m/M$. The corresponding Langevin equation contains nonlinear corrections to the…

Statistical Mechanics · Physics 2010-01-22 A. V. Plyukhin

We propose a prescription based on the Fokker-Planck equation in the Stratonovich approach, with the diffusion coefficient dependent on temporal and spatial coordinates, for describing heat conduction by phonons in small structures. This…

Soft Condensed Matter · Physics 2007-05-23 Kwok Sau Fa

An elementary system leading to the notions of fractional integrals and derivatives is considered. Various physical situations whose description is associated with fractional differential equations of motion are discussed.

Statistical Mechanics · Physics 2007-05-23 Alexander I. Olemskoi

This article studies a Fokker-Planck type equation of fractional diffusion with conservative drift $\partial$f/$\partial$t = $\Delta$^($\alpha$/2) f + div(Ef), where $\Delta$^($\alpha$/2) denotes the fractional Laplacian and E is a…

Analysis of PDEs · Mathematics 2020-01-22 Laurent Lafleche

We prove a new uniqueness result for solutions to Fokker-Planck-Kolmogorov (FPK) equations for probability measures on infinite-dimensional spaces. We consider infinite-dimensional drifts that admit certain finite-dimensional…

Distributed order fractional Langevin-like equations are introduced and applied to describe anomalous diffusion without unique diffusion or scaling exponent. It is shown that these fractional Langevin equations of distributed order can be…

Statistical Mechanics · Physics 2012-01-16 C. H. Eab , S. C. Lim
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