Results 251 to 260 of about 16,328 (286)

Generalized Langevin equation for an oscillator

Physical Review B, 1986
A central oscillator coupled to a bath of harmonic oscillators with a two-dimensional Debye spectrum is set up as a model for the dynamics of strongly coupled linear systems. The bath oscillators are eliminated from the central oscillator's equation of motion, other than for initial conditions. The resulting Langevin equation is solved analytically for
, Kemeny, , Mahanti, , Kaplan
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Langevin equations for fluctuating surfaces

Physical Review E, 2005
Exact Langevin equations are derived for the height fluctuations of surfaces driven by the deposition of material from a molecular beam. We consider two types of model: deposition models, where growth proceeds by the deposition and instantaneous local relaxation of particles, with no subsequent movement, and models with concurrent random deposition and
Alvin L-S, Chua, Christoph A, Haselwandter, Chiara, Baggio, Dimitri D, Vvedensky   +3 more
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The Langevin Equation

2014
In this chapter, we study the Langevin equation and the associated Fokker –Planck equation. In Sect. 6.1, we introduce the equation and study some of the main properties of the corresponding Fokker–Planck equation. In Sect. 6.2 we give an elementary introduction to the theories of hypoellipticity and hypocoercivity. In Sect.
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The Langevin Equation

2020
As a prelude, some of the important properties of the Maxwellian distribution of velocities in thermal equilibrium are highlighted. The basic equation of motion of a particle in a fluid incorporating the effects of random molecular collisions, the Langevin equation, is introduced.
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The Langevin Equation

1997
The generalized Langevin equation describes processes in a mechanical system with both deterministic and random forces which have comparable magnitudes (i.e., neither the deterministic nor random part can be neglected) and the random force is a transformed white noise. Examples of such processes are well known in physics.
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A Langevin Equation for the Turbulent Vorticity

2009
The vorticity field of fully developed turbulence displays a complex spatial structure consisting of a large number of entangled filamentary vortices (see illustration). As a consequence, the PDF of the vorticity shows a highly non-Gaussian shape with pronounced tails. In the present work a kinetic theory for the turbulent vorticity is presented. Under
Wilczek, M., Friedrich, R.
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The Langevin Equation

2000
The objective of this Lecture is to present the Langevin equation, which is a physically deduced equation of motion for particles in a fluid. The starting point is not the canonical ensemble; rather, this Lecture presents a rationale for postulating that the correct equation of motion has a particular mathematical form.
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The generalized Langevin equation

Journal of Physics A: General Physics, 1972
The simple Langevin equation describes a process which is both Markovian and Gaussian. A generalization of the Langevin equation allows us to deal with processes which are projections of n-dimensional Gaussian- Markov processes. The results are formally equivalent to generalizations proposed by Kubo in 1966 provided the second fluctuation-dissipation ...
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Derivation of the Langevin Equation

2014
In this chapter, we derive the Langevin equation from a simple mechanical model for a small system (which we will refer to as a Brownian particle) that is in contact with a thermal reservoir that is at thermodynamic equilibrium at time t = 0. The full dynamics, Brownian particle plus thermal reservoir, are assumed to be Hamiltonian.
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Attaining ergodicity in a Langevin equation with heterogeneous media

Chaos, Solitons and Fractals, 2022
Kwok Sau Fa
exaly