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Related papers: Diffusion in an expanding medium: Fokker-Planck eq…

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Fractional Brownian motion, a stochastic process with long-time correlations between its increments, is a prototypical model for anomalous diffusion. We analyze fractional Brownian motion in the presence of a reflecting wall by means of…

Statistical Mechanics · Physics 2018-02-21 Alexander H. O. Wada , Thomas Vojta

We consider subdiffusion in a system which consists of two media separated by a thin membrane. The subdiffusion parameters may be different in each of the medium. Using the new method presented in this paper we derive the probabilities (the…

Statistical Mechanics · Physics 2016-11-30 Tadeusz Kosztołowicz

We study a Brownian particle diffusing under a time-modulated stochastic resetting mechanism to a fixed position. The rate of resetting r(t) is a function of the time t since the last reset event. We derive a sufficient condition on r(t)…

Statistical Mechanics · Physics 2016-05-18 Arnab Pal , Anupam Kundu , Martin R. Evans

The temporal Fokker-Planck equation is analytically integrated in an arbitrary number of spatial dimensions but with the 2D and 3D results highlighted. It is shown that a temporal power-law ansatz for the anisotropic diffusion coefficients…

Classical Physics · Physics 2013-06-27 Billy D. Jones

The Fourier law and the diffusion equation are derived from the Schrodinger equation of a diffusive medium (consisting of a random potential). The theoretical model is backed by numerical simulation. This derivation can easily be…

Disordered Systems and Neural Networks · Physics 2008-12-31 Er'el Granot , Nisim Cohen , Shmuel Sternklar

A generalized Langevin equation is suggested to describe a system with memory($u(t,t') = \frac{1}{\Gamma (\nu )}(t - t')^\nu $) as well as with positive and negative damping. The equation can be transformed into the Fokker-Planck equation…

Physics and Society · Physics 2019-09-11 Peng Wang , Feng-Chun Pan , Jie Huo , Xu-Ming Wang

We study normal diffusive and subdiffusive processes in a harmonic potential (Ornstein-Uhlenbeck process) on a uniformly growing/contracting domain. Our starting point is a recently derived fractional Fokker-Planck equation, which covers…

Statistical Mechanics · Physics 2019-07-31 F. Le Vot , S. B. Yuste , E. Abad

We study the asymptotic and pre-asymptotic diffusive properties of Brownian particles in channels whose section varies periodically in space. The effective diffusion coefficient $D_{\mathrm{eff}}$ is numerically determined by the asymptotic…

Statistical Mechanics · Physics 2014-12-11 Giuseppe Forte , Fabio Cecconi , Angelo Vulpiani

We study the consequences of different realizations of diffusion processes in relativistic Langevin simulations. We elaborate on the Ito-Stratonovich dilemma by showing how microscopically calculated transport coefficients as obtained from…

Nuclear Theory · Physics 2015-06-15 Min He , Hendrik van Hees , Pol B. Gossiaux , Rainer J. Fries , Ralf Rapp

We study the problem of particles undergoing Brownian motion in an expanding sphere whose surface is an absorbing boundary for the particles. The problem is akin to that of the diffusion of impurities in a grain of polycrystalline material…

Statistical Mechanics · Physics 2009-11-13 Karl Forsberg , Ali R. Massih

We consider the Green's functions associated to a scalar field propagating on a curved, ultra-static background, in the presence of modified dispersion relations. The usual proper-time deWitt-Schwinger procedure to obtain a series…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Massimiliano Rinaldi

We show that for a subdiffusive continuous time random walk with scale-free waiting time distribution the first-passage dynamics on a finite interval can be optimised by introduction of a piecewise linear potential barrier. Analytical…

Statistical Mechanics · Physics 2014-12-24 Vladimir Palyulin , Ralf Metzler

We describe the theory of Fermi-type acceleration, including first-order Fermi acceleration at a parallel shock front and second-order Fermi acceleration in a test particle limit. Including the theory of the turbulent acceleration and the…

High Energy Astrophysical Phenomena · Physics 2018-07-11 Y. G. Zheng , G. B. Long , C. Y. Yang , J. M. Bai

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

Treating the motion of a dust particle suspended in a liquid as a random walk, Einstein in 1905 derived an equation describing the diffusion of the particle's probability distribution in configuration space. Fokker and Planck extended this…

Astrophysics · Physics 2009-11-11 Edmund Bertschinger

We consider the diffusion of a non-relativistic heavy quark of fixed mass M, in a one-dimensionally expanding and strongly coupled plasma using the AdS/CFT duality. The Green's function constructed around a static string embedded in a…

High Energy Physics - Theory · Physics 2008-11-26 Keun-Young Kim , Sang-Jin Sin , Ismail Zahed

We study the Fokker-Planck equation for an active particle with both the radial and tangential forces and the perturbative force. We find the solution of the joint probability density. In the limit of the long-time domain and for the…

Statistical Mechanics · Physics 2024-10-15 Jae-Won Jung , Sung Kyu Seo , Sungchul Kwon , Kyungsik Kim

We show that when Brownian motion takes place in a heterogeneous medium, the presence of local forces and transport coefficients leads to deviations from a Gaussian probability distribution that make that the ratio between forward and…

Soft Condensed Matter · Physics 2016-12-21 Paolo Malgaretti , Ignacio Pagonabarraga Miguel J. Rubi

The Smoluchowski coagulation-diffusion PDE is a system of partial differential equations modelling the evolution in time of mass-bearing Brownian particles which are subject to short-range pairwise coagulation. This survey presents a fairly…

Probability · Mathematics 2019-02-14 Alan Hammond

We study the dynamics of Brownian particles in a heterogeneous one-dimensional medium with a spatially-dependent diffusion coefficient of the form $D(x)\sim |x|^c$, at constant temperature. The particle's probability distribution function…

Statistical Mechanics · Physics 2016-08-03 Shaked Regev , Niels Grønbech-Jensen , Oded Farago