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The Landau--Lifshitz--Gilbert equations for the evolution of the magnetization, in presence of an external torque, can be cast in the form of the Lorenz equations and, thus, can describe chaotic fluctuations. To study quantum effects, we…

Quantum Physics · Physics 2015-04-24 Julien Tranchida , Pascal Thibaudeau , Stam Nicolis

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

We relate the memory kernel in the Nakajima-Zwanzig-Mori time-convolution approach to the reduced system propagator which is often used to obtain the kernel in the Tokuyama-Mori time-convolutionless approach. The connection provides a…

Other Condensed Matter · Physics 2018-09-14 Lyran Kidon , Haobin Wang , Michael Thoss , Eran Rabani

Starting from the kinetic equations for the fluctuations and correlations of a dilute gas of inelastic hard spheres or disks, a Boltzmann-Langevin equation for the one-particle distribution function of the homogeneous cooling state is…

Statistical Mechanics · Physics 2015-05-13 J. Javier Brey , P. Maynar , M. I. Garcia de Soria

Study of Langevin dynamics and the fluctuation-dissipation relation (FDR) for a generic probe system (represented by a mass $M$), bilinearly coupled to a bath of harmonic oscillators, has been a standard paradigm for a microscopic theory of…

Statistical Mechanics · Physics 2018-04-04 Chitrak Bhadra

We study the dynamics of generic reaction-diffusion fronts, including pulses and chemical waves, in the presence of multiplicative noise. We discuss the connection between the reaction-diffusion Langevin-like field equations and the…

Statistical Mechanics · Physics 2009-11-07 A. Rocco , L. Ramirez-Piscina , J. Casademunt

We propose a Langevin equation to describe the quantum Brownian motion of bounded particles based on a distinctive formulation concerning both the fluctuation and dissipation forces. The fluctuation force is similar to that employed in the…

Statistical Mechanics · Physics 2020-04-22 Mário J. de Oliveira

We consider the effects of long-range temporal correlations in many-particle systems, focusing particularly on fluctuations about the typical behaviour. For a specific class of memory dependence we discuss the modification of the large…

Statistical Mechanics · Physics 2015-12-24 Rosemary J. Harris

Brownian motion of single particles with various masses M and diameters D is studied by molecular dynamics simulations. Besides the momentum auto-correlation function of the Brownian particle the memory function and the fluctuating force…

Chemical Physics · Physics 2015-05-20 Hyun Kyung Shin , Changho Kim , Peter Talkner , Eok Kyun Lee

The generalized elastic model encompasses several physical systems such as polymers, membranes, single file systems, fluctuating surfaces and rough interfaces. We consider the case of an applied localized potential, namely an external force…

Statistical Mechanics · Physics 2012-03-16 Alessandro Taloni , Aleksei Chechkin , Joseph Klafter

A kernel-based framework for spatio-temporal data analysis is introduced that applies in situations when the underlying system dynamics are governed by a dynamic equation. The key ingredient is a representer theorem that involves…

Statistics Theory · Mathematics 2020-11-16 Oleg Szehr , Dario Azzimonti , Laura Azzimonti

We generalize the oscillator model of a particle interacting with a thermal reservoir by introducing arbitrary nonlinear couplings in the particle coordinates.The equilibrium positions of the heat bath oscillators are promoted to space-time…

High Energy Physics - Theory · Physics 2009-10-28 F. Illuminati , M. Patriarca , P. Sodano

The Mori-Zwanzig projection operator formalism is a powerful method for the derivation of mesoscopic and macroscopic theories based on known microscopic equations of motion. It has applications in a large number of areas including fluid…

Statistical Mechanics · Physics 2019-06-26 Michael te Vrugt , Raphael Wittkowski

We complete the kinetic theory of inhomogeneous systems with long-range interactions initiated in previous works. We use a simpler and more physical formalism. We consider a system of particles submitted to a small external stochastic…

Statistical Mechanics · Physics 2023-08-23 Pierre-Henri Chavanis

The time-dependent transmission coefficient for the Kramers problem exhibits different behaviors in different parameter regimes. In the high friction regime it decays monotonically ("non-adiabatic"), and in the low friction regime it decays…

Statistical Mechanics · Physics 2009-10-31 Ramon Reigada , Aldo H. Romero , Katja Lindenberg , Jose M. Sancho

We establish a machine learning model for the prediction of the magnetization dynamics as function of the external field described by the Landau-Lifschitz-Gilbert equation, the partial differential equation of motion in micromagnetism. The…

Computational Physics · Physics 2021-07-27 Lukas Exl , Norbert J. Mauser , Sebastian Schaffer , Thomas Schrefl , Dieter Suess

We derive a generalized quantum Langevin equation and its fluctuation-dissipation relation describing the quantum dynamics of a tagged particle interacting with a medium (environment), where both the particle and the environment are driven…

Quantum Physics · Physics 2025-07-11 Daniele Gamba , Bingyu Cui , Alessio Zaccone

We write equations of motion for density variables that are equivalent to Newtons equations. We then propose a set of trial equations parameterised by two unknown functions to describe the exact equations. These are chosen to best fit the…

Soft Condensed Matter · Physics 2009-11-07 E. Zaccarelli , G. Foffi , P. De Gregorio , F. Sciortino , P. Tartaglia , K. A. Dawson

A universal kernel is constructed whose sections approximate any causal and time-invariant filter in the fading memory category with inputs and outputs in a finite-dimensional Euclidean space. This kernel is built using the reservoir…

Machine Learning · Computer Science 2025-09-05 Lukas Gonon , Lyudmila Grigoryeva , Juan-Pablo Ortega

Fundamental understanding of complex dynamics in many-particle systems on the atomistic level is of utmost importance. Often the systems of interest are of macroscopic size but can be partitioned into few important degrees of freedom which…

Chemical Physics · Physics 2015-07-09 Fabian Gottwald , Sven Karsten , Sergei D. Ivanov , Oliver Kühn