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We study a gas of hard rods on a ring, driven by an external thermostat, with either elastic or inelastic collisions, which exhibits sub-diffusive behavior $<x^2 > \sim t^{1/2}$. We show the validity of the usual Fluctuation-Dissipation…

Statistical Mechanics · Physics 2008-10-10 D. Villamaina , A. Puglisi , A. Vulpiani

A theory for non-equilibrium systems is derived from a maximum entropy approach similar in spirit to the equilibrium theory given by Gibbs. Requiring Hamilton's principle of stationary action to be satisfied on average during a trajectory,…

Statistical Mechanics · Physics 2019-02-04 David M. Rogers , Susan B. Rempe

Although an intimate relation between entropy and diffusion has been advocated for many years and even seems to have been verified in theory and experiments, a quantitatively reliable study, and any derivation of an algebraic relation…

Statistical Mechanics · Physics 2020-07-22 Subhajit Acharya , Biman Bagchi

A particle with internal unobserved states diffusing in a force field will generally display effective advection-diffusion. The drift velocity is proportional to the mobility averaged over the internal states, or effective mobility, while…

Statistical Mechanics · Physics 2017-10-13 Erik Aurell , Stefano Bo

A stochastic differential equation that describes the dynamics of single-domain magnetic particles at any temperature is derived using a classical formalism. The deterministic terms recover existing theory and the stochastic process takes…

Mesoscale and Nanoscale Physics · Physics 2015-10-28 Michail Tzoufras , Gregory J. Parker , Michael K. Grobis

We consider a biaxial macrospin with an easy and hard axis, and study its dynamical evolution under the combined effects of thermal noise and spin transfer torque. The spin-torque is associated with both a perpendicularly magnetized…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 Daniele Pinna , Daniel L. Stein , Andrew D. Kent

We introduce and analyze a model for the transport of particles or energy in extended lattice systems. The dynamics of the model acts on a discrete phase space at discrete times but has nonetheless some of the characteristic properties of…

Mathematical Physics · Physics 2015-06-12 Raphael Lefevere

It is shown that the electron spin may not be conserved after a spin-independent scattering. This fact strongly limits the validity of the classical model of spin-up/spin-down bands, which has been used for description of magnetic…

Materials Science · Physics 2013-04-09 Vadym Zayets

Recently a new theory for the transport of energetic particles across a mean magnetic field was presented. Compared to other non-linear theories the new approach has the advantage that it provides a full time-dependent description of the…

Plasma Physics · Physics 2017-09-20 Jordan Lasuik , Andreas Shalchi

We investigate the microscopic features of bosonic quantum transport in a non-equilibrium steady state, which breaks time reversal invariance spontaneously. The analysis is based on the probability distributions, generated by the…

Statistical Mechanics · Physics 2022-04-19 Mihail Mintchev , Luca Santoni , Paul Sorba

We analyze a system of stochastic differential equations describing the joint motion of a massive (inert) particle in a viscous fluid in the presence of a gravitational field and a Brownian particle impinging on it from below, which…

Probability · Mathematics 2020-01-07 Sayan Banerjee , Brendan Brown

Translationally diffusive behavior arising from the combination of orientational diffusion and powered motion at microscopic scales is a known phenomenon, but the peculiarities of the evolution of expected position conditioned on initial…

Soft Condensed Matter · Physics 2016-09-21 Amir Nourhani , Stephen J. Ebbens , John G. Gibbs , Paul E. Lammert

We present a theoretical framework to understand a modified fluctuation-dissipation theorem valid for systems close to non-equilibrium steady-states and obeying markovian dynamics. We discuss the interpretation of this result in terms of…

Statistical Mechanics · Physics 2015-05-20 G. Verley , K. Mallick , D. Lacoste

The influence of the intrinsic spin of electrons on the propagation of circularly polarized waves in a magnetized plasma is considered. New eigenmodes are identified, one of which propagates below the electron cyclotron frequency, one above…

Plasma Physics · Physics 2015-05-19 A. P. Misra , G. Brodin , M. Marklund , P. K. Shukla

The problem of anomalous diffusion in momentum space is considered for plasma-like systems on the basis of a new collision integral, which is appropriate for consideration of the probability transition function (PTF) with long tails in…

Statistical Mechanics · Physics 2015-05-18 S. A. Trigger , W. Ebeling , G. J. F. van Heijst , P. P. J. M. Schram , I. M. Sokolov

Diffusion and rectification of Brownian particles powered by a rotating wheel are numerically investigated in a two-dimensional channel. The nonequilibrium driving comes from the rotating wheel, which can break thermodynamical equilibrium…

Statistical Mechanics · Physics 2017-07-24 Bao-quan Ai

Brownian diffusion of rod-like polymers in the presence of randomly distributed spherical obstacles is studied using molecular dynamics (MD) simulations. It is observed that dependence of the reduced diffusion coefficient of these…

Soft Condensed Matter · Physics 2015-05-20 Farzaneh Sakha , Hossein Fazli

The transport of charged particles in various astrophysical environments permeated by magnetic fields is described in terms of a diffusion process, which relies on diffusion-tensor parameters generally inferred from Monte-Carlo simulations.…

High Energy Astrophysical Phenomena · Physics 2022-12-09 Olivier Deligny

Various astrophysical studies have motivated the investigation of the transport of high energy particles in magnetic turbulence, either in the source or en route to the observation sites. For strong turbulence and large rigidity, the…

High Energy Astrophysical Phenomena · Physics 2011-07-08 I. Plotnikov , G. Pelletier , M. Lemoine

Non-equilibrium stochastic dynamics of several active Brownian systems are modeled in terms of non-linear velocity dependent force. In general, this force may consist of both even and odd functions of velocity. We derive the expression for…

Statistical Mechanics · Physics 2016-09-14 Debasish Chaudhuri