Rotational Brownian motion of spherical molecules the Fokker-Planck equation with memory

1996 ◽  
Vol 229 (3-4) ◽  
pp. 501-514 ◽  
Author(s):  
A.P Blokhin ◽  
M.F Gelin
Keyword(s):  
Brownian Motion ◽  
Planck Equation ◽  
Fokker Planck Equation ◽  
With Memory ◽  
Rotational Brownian Motion ◽  
Fokker Planck

Brownian Motion on Cantor Sets

2020 ◽  
Vol 21 (3-4) ◽  
pp. 275-281
Author(s):  
Ali Khalili Golmankhaneh ◽  
Saleh Ashrafi ◽  
Dumitru Baleanu ◽  
Arran Fernandez
Keyword(s):  
Brownian Motion ◽  
Classical Method ◽  
Mean Square Displacement ◽  
Planck Equation ◽  
Cantor Sets ◽  
Mean Square ◽  
Fokker Planck Equation ◽  
Fractal Time ◽  
The Mean ◽  
Fokker Planck

AbstractIn this paper, we have investigated the Langevin and Brownian equations on fractal time sets using Fα-calculus and shown that the mean square displacement is not varied linearly with time. We have also generalized the classical method of deriving the Fokker–Planck equation in order to obtain the Fokker–Planck equation on fractal time sets.

Brownian Motion of Rotating Particles

1968 ◽  
Vol 23 (4) ◽  
pp. 597-609 ◽  
Author(s):  
Siegfried Hess
Keyword(s):  
Brownian Motion ◽  
Angular Velocity ◽  
Brownian Particle ◽  
Planck Equation ◽  
Transverse Force ◽  
Particle Collision ◽  
Fokker Planck Equation ◽  
Rotational Motions ◽  
Transport Relaxation ◽  
Fokker Planck

A kinetic theory for the Brownian motion of spherical rotating particles is given starting from a generalized Fokker-Planck equation. The generalized Fokker-Planck collision operator is a sum of two ordinary Fokker-Planck differential operators in velocity and angular velocity space respectively plus a third term which provides a coupling of translational and rotational motions. This term stems from a transverse force proportional to the cross product of velocity and angular velocity of a Brownian particle. Collision brackets pertaining to the generalized Fokker-Planck operator are defined and their general properties are discussed. Application of WALDMANN'S moment method to the Fokker-Planck equation yields a set of coupled linear differential equations (transport-relaxation equations) for certain local mean values. The constitutive laws for diffusion, heat conduction by Brownian particles and spin diffusion are deduced from the transport-relaxation equations. The transport-relaxations coefficients appearing in them are given in terms of the two friction coefficients for the damping of translational and rotational motions and a third coefficient which is a measure of the transverse force. By the coupling of translational and rotational motions a diffusion flow gives rise to a correlation of linear and angular velocities.

scholarly journals Diffusion and Memory Effect in a Stochastic Processes and the Correspondence to an Information Propagation in a Social System

2021 ◽  
Author(s):  
Peng Wang ◽  
Jie Huo ◽  
Xu-Ming Wang
Keyword(s):  
Social System ◽  
Particle System ◽  
Planck Equation ◽  
Generalized Langevin Equation ◽  
Information Propagation ◽  
Fokker Planck Equation ◽  
Social Ideology ◽  
Diffusion Particle ◽  
With Memory ◽  
Fokker Planck

Abstract A generalized Langevin equation is suggested to describe a diffusion particle system with memory. The equation can be transformed into the Fokker-Planck equation by using the Kramers-Moyal expansion. The solution of Fokker-Planck equation can describe not only the diffusion of particles but also that of opinion particles based on the similarities between the two. We find that the memory can restrain some non-equilibrium phenomena of velocity distribution in the system, without memory, induced by correlation between the noise and space[1]. However, the memory can enhance the effective collision among particles as shown by the variation of diffusion coefficients, and changes the diffusion mode between the dissipative and pumping region by comparing with that in the aforementioned system without memory. As the discussions in this physical system is paralleled to a social system, the random diffusion of social ideology, such as the information propagation, can be suppressed by the correlation between the noise and space.

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