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We examine characteristic properties of deterministic and stochastic diffusion in low-dimensional chaotic dynamical systems. As an example, we consider a periodic array of scatterers defined by a simple chaotic map on the line. Adding…

Chaotic Dynamics · Physics 2009-11-07 R. Klages

We study diffusion in systems of classical particles whose dynamics conserves the total center of mass. This conservation law leads to several interesting consequences. In finite systems, it allows for equilibrium distributions that are…

Statistical Mechanics · Physics 2024-01-04 Jung Hoon Han , Ethan Lake , Sunghan Ro

We consider an energy conserving linear dynamics that we perturb by a Glauber dynamics with random site dependent intensity. We prove hydrodynamic limits for this non-reversible system in random media. The diffusion coefficient turns out to…

Statistical Mechanics · Physics 2015-05-28 Cedric Bernardin

In this paper the multi-dimensional random walk models governed by distributed fractional order differential equations and multi-term fractional order differential equations are constructed. The scaling limits of these random walks to a…

Classical Analysis and ODEs · Mathematics 2007-05-23 Sabir Umarov , Stanly Steinberg

Observations of galactic white dwarfs with Gaia have allowed for unprecedented modeling of white dwarf cooling, resolving core crystallization and sedimentary heating from neutron rich nuclei. These cooling sequences are sensitive to the…

Solar and Stellar Astrophysics · Physics 2021-07-07 M. E. Caplan , I. F. Freeman

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

This is the second of a series of papers devoted to develop a microscopical approach to the dipole emission process and its relation to coherent transport in random media. In this Letter, we deduce a relation between the transverse decay…

Optics · Physics 2009-03-12 M. Donaire

The invariance for the equation of fast diffusion in the 2D coordinate space has been proved, and its reduction to the 1D (with respect to the spatial variable) analog is demonstrated. On the basis of these results, new exact…

Mathematical Physics · Physics 2007-05-23 E. I. Semenov

Application of fractional calculus to the description of anomalous diffusion and relaxation processes in complex media provided one of the most impressive impulses to the development of statistical physics during the last decade. In…

Soft Condensed Matter · Physics 2008-11-13 A. E. Sitnitsky

The diffusion coefficient of a circular shaped inclusion in a liquid membrane is investigated by taking into account the interaction between membranes and bulk solvents of arbitrary thickness. As illustrative examples, the diffusion…

Soft Condensed Matter · Physics 2015-05-28 Kazuhiko Seki , Sanoop Ramachandran , Shigeyuki Komura

We measure diffusion coefficients in the lamellar phase of the nonionic binary system C$_{12}$EO$_6$/H$_2$O using fluorescence recovery after photobleaching. The diffusion coefficient across the lamellae shows an abrupt increase upon…

Soft Condensed Matter · Physics 2015-04-20 Doru Constantin , Patrick Oswald

Riemannian diffusion models draw inspiration from standard Euclidean space diffusion models to learn distributions on general manifolds. Unfortunately, the additional geometric complexity renders the diffusion transition term inexpressible…

Machine Learning · Computer Science 2023-11-01 Aaron Lou , Minkai Xu , Stefano Ermon

Diffusion magnetic resonance has been employed for determining the distribution of net displacements (ensemble average propagator), moments and correlations of net displacements, and the steady-state distribution of magnetized particles.…

Materials Science · Physics 2021-05-04 Evren Özarslan

In the present work, we investigate the potential of fractional derivatives to model atmospheric dispersion of pollutants. We propose simple fractional differential equation models for the steady state spatial distribution of concentration…

Atmospheric and Oceanic Physics · Physics 2017-02-22 A. G. O. Goulart , M. J. Lazo , J. M. S. Suarez , D. M. Moreira

I present a first-principles theory of diffusion-limited aggregation in two dimensions. A renormalized mean-field approximation gives the form of the unstable manifold for branch competition, following the method of Halsey and Leibig [Phys.…

Condensed Matter · Physics 2009-10-22 Thomas C. Halsey

The aim of this work is to study the effect of diffusion on the stability of the equilibria in a general two-components reaction-diffusion system with Neumann boundary conditions in the space of continuous functions. As by product, we…

Analysis of PDEs · Mathematics 2023-12-19 Francisco J. Vielma-Leal , Miguel A. D. R. Palma , Miguel Montenegro-Concha

The presence of resonances modifies the passage of light or of electrons through a disordered medium. We generalize random matrix theory to account for this effect. Using supersymmetry, we calculate analytically the mean density of states,…

Disordered Systems and Neural Networks · Physics 2009-10-31 B. Elattari , V. Kagalovsky , H. A. Weidenmueller

We study front propagation in the reversible reaction-diffusion system A + A <-> A on a 1-d lattice. Extending the idea of leading particle in studying the motion of the front we write a master equation in the stochastically moving frame…

Statistical Mechanics · Physics 2009-11-11 Niraj Kumar , Goutam Tripathy

In this work, we study an inverse problem of recovering a space-time dependent diffusion coefficient in the subdiffusion model from the distributed observation, where the mathematical model involves a Djrbashian-Caputo fractional derivative…

Numerical Analysis · Mathematics 2022-09-23 Bangti Jin , Zhi Zhou

This paper is concerned with the study of Green's functions for one dimensional diffusions with constant diffusion coefficient and linear time inhomogeneous drift. It is well know that the whole line Green's function is given by a Gaussian.…

Analysis of PDEs · Mathematics 2021-03-09 Joseph G. Conlon , Michael Dabkowski