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Anomalous transport processes in which the variance of the distance travelled does not necessarily increase linearly with time are modelled using the formalism of continuous time random walks. We compute particle propagators which have the…

Astrophysics · Physics 2011-05-23 B. R. Ragot , J. G. Kirk

It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum…

Quantum Physics · Physics 2007-05-23 K. Murr , P. Maunz , P. W. H. Pinkse , T. Puppe , I. Schuster , D. Vitali , G. Rempe

Numerical computations of transport coefficients at low temperatures are presented for shapes typically encountered in nuclear fission. The influence of quantum effects of the nucleonic degrees of freedom is examined, with pair correlations…

Nuclear Theory · Physics 2009-10-31 H. Hofmann , F. A. Ivanyuk

Molecular dynamics simulations are used to study different definitions of contact at the atomic scale. The roles of temperature, adhesive interactions and atomic structure are studied for simple geometries. An elastic, crystalline substrate…

Materials Science · Physics 2015-03-14 Shengfeng Cheng , Mark O. Robbins

Prompted by recent experimental developments, a theory of surface scattering of fast atoms at grazing incidence is developed. The theory gives rise to a quantum mechanical limit for ordered surfaces that describes coherent diffraction peaks…

Atomic Physics · Physics 2022-09-23 J. R. Manson , Hocine Khemliche , Philippe Roncin

Analysis of signal fluctuations of a locally fixed probe, caused by molecules diffusing under the probe, can be used to determine diffusion coefficients. Theoretical treatments so far have been limited to point-like particles or to…

Statistical Mechanics · Physics 2015-06-18 Susanne Hahne , Philipp Maass

Atomicity is a ubiquitous assumption in distributed computing, under which actions are indivisible and appear sequential. In classical computing, this assumption has several theoretical and practical guarantees. In quantum computing,…

Quantum Physics · Physics 2024-04-30 Zhicheng Zhang , Mingsheng Ying

We briefly review some aspects of the anomalous diffusion, and its relevance in reactive systems. In particular we consider {\it strong anomalous} diffusion characterized by the moment behaviour $\langle x(t)^q \rangle \sim t^{q \nu(q)}$,…

Statistical Mechanics · Physics 2016-09-06 Fabio Cecconi , Davide Vergni , Angelo Vulpiani

This paper presents an overview of recent computer simulations of grain boundary (GB) diffusion focusing on atomistic understanding of diffusion mechanisms. At low temperatures when GB structure is ordered, diffusion is mediated by point…

Materials Science · Physics 2019-04-25 Y. Mishin

Translational diffusion coefficients are routinely estimated from molecular dynamics simulations. Linear fits to mean squared displacement (MSD) curves have become the de facto standard, from simple liquids to complex biomacromolecules.…

Computational Physics · Physics 2020-11-20 Jakob Tómas Bullerjahn , Sören von Bülow , Gerhard Hummer

A new approach to thermo-quantum diffusion is proposed and a nonlinear quantum Smoluchowski equation is derived, which describes classical diffusion in the field of the Bohm quantum potential. A nonlinear thermo-quantum expression for the…

Quantum Physics · Physics 2011-04-18 Roumen Tsekov

Molecular dynamics simulations are used to study the mechanism and kinetics of hydrated electron diffusion. The electron center of mass is found to exhibit Brownian-type behavior with a diffusion coefficient considerably greater than that…

Chemical Physics · Physics 2012-11-06 Kafui A. Tay , François-Xavier Coudert , Anne Boutin

Depending on their mechanism of self-propulsion, active particles can exhibit a time-dependent, often periodic, propulsion velocity. The precise propulsion velocity profile determines their mean square displacement and their effective…

Soft Condensed Matter · Physics 2024-05-06 Arnau Jurado Romero , Carles Calero , Rossend Rey

Hot-atoms reactions mechanisms bring about reaction rates which are several orders of magnitude higher than those expected in the case of ad-atoms which have thermalized with the surface. This paper addresses the issue of a possible…

Materials Science · Physics 2015-06-11 Massimo Tomellini

We consider a deformable body immersed in an incompressible liquid that is randomly stirred. Sticking to physical situations in which the body departs only slightly from its spherical shape, we calculate the diffusion constant of the body.…

Statistical Mechanics · Physics 2009-11-07 Gady Frenkel , Moshe Schwartz

Reaction-diffusion equations are one of the most common mathematical models in the natural sciences and are used to model systems that combine reactions with diffusive motion. However, rather than normal diffusion, anomalous subdiffusion is…

Statistical Mechanics · Physics 2021-04-23 Amanda M Alexander , Sean D Lawley

In the dynamics of atoms and molecules at metal surfaces, electron-hole pair excitations can play a crucial role. In the case of hyperthermal hydrogen atom scattering, they lead to nonadiabatic energy loss and highly inelastic scattering.…

Materials Science · Physics 2024-12-02 Connor L. Box , Nils Hertl , Wojciech G. Stark , Reinhard J. Maurer

The equation which describes a particle diffusing in a logarithmic potential arises in diverse physical problems such as momentum diffusion of atoms in optical traps, condensation processes, and denaturation of DNA molecules. A detailed…

Statistical Mechanics · Physics 2015-06-03 Ori Hirschberg , David Mukamel , Gunter M. Schütz

Heat diffusion describes the process by which heat flows from areas with higher temperatures to ones with lower temperatures. This concept was previously adapted to graph structures, whereby heat flows between nodes of a graph depending on…

Signal Processing · Electrical Eng. & Systems 2024-05-01 Stephan Goerttler , Fei He , Min Wu

Reaction-diffusion equations are widely used as the governing evolution equations for modeling many physical, chemical, and biological processes. Here we derive reaction-diffusion equations to model transport with reactions on a…

Statistical Mechanics · Physics 2020-09-16 E. Abad , C. N. Angstmann , B. I. Henry , A. V. McGann , F. Le Vot , S. B. Yuste