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Related papers: Spectral dimension and diffusion in multi-scale sp…

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In this paper we analyze fractional Fokker-Planck equation describing subdiffusion in the general infinitely divisible (ID) setting. We show that in the case of space-time-dependent drift and diffusion and time-dependent jump coefficient,…

Probability · Mathematics 2015-10-01 Marcin Magdziarz , Tomasz Zorawik

General self-consistent expressions for the coefficients of diffusion and dynamical friction in a stable, bound, multicomponent self-gravitating and inhomogeneous system are derived. They account for the detailed dynamics of the colliding…

Astrophysics of Galaxies · Physics 2017-06-20 Jean Heyvaerts , Jean-Baptiste Fouvry , Pierre-Henri Chavanis , Christophe Pichon

The friction coefficient of a particle can depend on its position as it does when the particle is near a wall. We formulate the dynamics of particles with such state-dependent friction coefficients in terms of a general Langevin equation…

Soft Condensed Matter · Physics 2009-11-13 A. W. C. Lau , T. C. Lubensky

We study the diffusion equation in two-dimensional quantum gravity, and show that the spectral dimension is two despite the fact that the intrinsic Hausdorff dimension of the ensemble of two-dimensional geometries is very different from…

High Energy Physics - Lattice · Physics 2009-10-31 J. Ambjorn , K. N. Anagnostopoulos , T. Ichihara , L. Jensen , Y. Watabiki

Different approaches to quantum gravity generally predict that the dimension of spacetime at the fundamental level is not 4. The principal tool to measure how the dimension changes between the IR and UV scales of the theory is the spectral…

High Energy Physics - Theory · Physics 2020-10-07 Michał Eckstein , Tomasz Trześniewski

We informally review the construction of spacetime geometries with multifractal and, more generally, multiscale properties. Based on fractional calculus, these continuous spacetimes have their dimension changing with the scale; they display…

High Energy Physics - Theory · Physics 2012-10-10 Gianluca Calcagni

We present a numerical study of classical particles diffusing on a solid surface. The particles' motion is modeled by an underdamped Langevin equation with ordinary thermal noise. The particle-surface interaction is described by a periodic…

Statistical Mechanics · Physics 2009-11-10 J. M. Sancho , A. M. Lacasta , K. Lindenberg , I. M. Sokolov , A. H. Romero

We show that the quantum stochastic unitary dynamics Langevin model for continuous in time measurements provides an exact formulation of the Heisenberg uncertainty error-disturbance principle. Moreover, as it was shown in the 80's, this…

Mathematical Physics · Physics 2015-06-26 V. P. Belavkin

We derive exact Langevin-type equations governing quasispecies dynamics. The inherent multiplicative noise has both real and imaginary parts. The numerical simulation of the underlying complex stochastic partial differential equations is…

Statistical Mechanics · Physics 2007-05-23 David Hochberg , M. -P. Zorzano , Federico Moran

In computing the spectra of quantum mechanical systems one encounters the Fourier transforms of time correlation functions, as given by the quantum regression theorem for systems described by master equations. Quantum state diffusion (QSD)…

Quantum Physics · Physics 2015-06-26 Todd A. Brun , Nicolas Gisin

Subdiffusive behavior of one-dimensional stochastic systems can be described by time-subordinated Langevin equations. The corresponding probability density satisfies the time-fractional Fokker-Planck equations. In the homogeneous systems…

Statistical Mechanics · Physics 2015-07-01 Rytis Kazakevicius , Julius Ruseckas

Generative diffusion models apply the concept of Langevin dynamics in physics to machine leaning, attracting a lot of interests from engineering, statistics and physics, but a complete picture about inherent mechanisms is still lacking. In…

Statistical Mechanics · Physics 2025-01-07 Zhendong Yu , Haiping Huang

The generation of non-separable, physically motivated covariance functions is a theme of ongoing research interest, given that only a few classes of such functions are available. We construct a non-separable space-time covariance function…

Methodology · Statistics 2016-12-20 Dionissios T. Hristopulos , Ivi C. Tsantili

The so-called spectral dimension is a scale-dependent number associated with both geometries and field theories that has recently attracted much attention, driven largely though not exclusively by investigations of causal dynamical…

High Energy Physics - Theory · Physics 2011-12-12 Thomas P. Sotiriou , Matt Visser , Silke Weinfurtner

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

Consistent quantum formalism based on the localized basis of the Wannirer functions in Heisenberg and Schrodinger pictures to describe propagation of electromagnetic field in a three dimensional media including diffraction is presented. In…

Quantum Physics · Physics 2015-06-26 V. N. Gorbachev , A. I. Zhiliba

We investigate the ensemble and time averaged mean squared displacements for particle diffusion in a simple model for disordered media by assuming that the local diffusivity is both fluctuating in time and has a deterministic average growth…

Statistical Mechanics · Physics 2016-10-05 A. G. Cherstvy , R. Metzler

The stochastic solution with Gaussian stationary increments is establihsed for the symmetric space-time fractional diffusion equation when $0 < \beta < \alpha \le 2$, where $0 < \beta \le 1$ and $0 < \alpha \le 2$ are the fractional…

Statistical Mechanics · Physics 2016-03-18 Gianni Pagnini , Paolo Paradisi

The Langevin equation is a common tool to model diffusion at a single-particle level. In non-homogeneous environments, such as aqueous two-phase systems or biological condensates with different diffusion coefficients in different phases,…

We consider a simple quantum system subjected to a classical random force. Under certain conditions it is shown that the noise-averaged Wigner function of the system follows an integro-differential stochastic Liouville equation. In the…

High Energy Physics - Theory · Physics 2008-02-03 Salman Habib