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The definition of a consistent evolution equation for statistical hybrid quantum-classical systems is still an open problem. In this paper we analyze the case of Ehrenfest dynamics on systems defined by a probability density and identify…

Quantum Physics · Physics 2023-08-30 J. L. Alonso , C. Bouthelier-Madre , J. Clemente-Gallardo , D. Martínez-Crespo , J. Pomar

We show that the quantum stochastic unitary dynamics Langevin model for continuous in time measurements provides an exact formulation of the Heisenberg uncertainty error-disturbance principle. Moreover, as it was shown in the 80's, this…

Mathematical Physics · Physics 2015-06-26 V. P. Belavkin

Diffusion of small particles is omnipresent in a plentiful number of processes occurring in Nature. As such, it is widely studied and exerted in almost all branches of sciences. It constitutes such a broad and often rather complex subject…

Statistical Mechanics · Physics 2023-01-11 Jakub Spiechowicz , Ivan G. Marchenko , Peter Hänggi , Jerzy Łuczka

The Ehrenfest dynamics, representing a quantum-classical mean-field type coupling, is a widely used approximation in quantum molecular dynamics. In this paper, we propose a time-splitting method for an Ehrenfest dynamics, in the form of a…

Numerical Analysis · Mathematics 2022-10-19 Di Fang , Shi Jin , Christof Sparber

Surface diffusion of small adsorbates is analyzed in terms of the so-called intermediate scattering function and dynamic structure factor, observables in experiments using the well-known quasielastic Helium atom scattering and Helium spin…

Statistical Mechanics · Physics 2018-09-26 S. Miret-Artés

This paper is concerned with a class of multivariable stochastic Hamiltonian systems whose generalised position is related by an ordinary differential equation to the momentum governed by an Ito stochastic differential equation. The latter…

Mathematical Physics · Physics 2023-12-18 Igor G. Vladimirov

We propose a very accurate computational scheme for the dynamics of a classical oscillator coupled to a molecular junction driven by a finite bias, including the finite mass effect. We focus on two minimal models for the molecular junction:…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 A. Nocera , C. A. Perroni , V. Marigliano Ramaglia , V. Cataudella

We propose a microscopic stochastic approach to improve description of nuclear dynamics beyond the mean-field approximation at low energies. It is shown that, for small amplitude fluctuations, the proposed model gives a result for the…

Nuclear Theory · Physics 2009-11-13 Sakir Ayik

A model has two main aims: predicting the behavior of a physical system and understanding its nature, that is how it works, at some desired level of abstraction. A promising recent approach to model building consists in deriving a…

Statistical Mechanics · Physics 2019-02-26 Marco Baldovin , Andrea Puglisi , Angelo Vulpiani

Quantum dynamics (e.g., the Schr\"odinger equation) and classical dynamics (e.g., Hamilton equations) can both be formulated in equal geometric terms: a Poisson bracket defined on a manifold. The difference between both worlds is due to the…

Quantum Physics · Physics 2010-10-08 J. L. Alonso , A. Castro , J. Clemente-Gallardo , J. C. Cuchí , P. Echenique , F. Falceto

In this work, we study the nonequilibrium statistical properties of the relaxation dynamics of a nanoparticle trapped in a harmonic potential. We report an exact time-dependent analytical solution to the Langevin dynamics that arises from…

Statistical Mechanics · Physics 2016-11-23 Domingos S. P. Salazar , Sérgio A. Lira

Inspired by one--dimensional light--particle systems, the dynamics of a non-Hamiltonian system with long--range forces is investigated. While the molecular dynamics does not reach an equilibrium state, it may be approximated in the…

Statistical Mechanics · Physics 2019-01-23 Romain Bachelard , Nicola Piovella , Shamik Gupta

A Langevin equation is suggested to describe a system driven by correlated Gaussian white noise as well as with positive and negative damping demarcated by a critical velocity. The equation can be transformed into the Fokker-Planck equation…

Physics and Society · Physics 2019-09-11 Peng Wang , Feng-Chun Pan , Jie Huo , Xu-Ming Wang

A procedure is introduced for deriving a coarse-grained dissipative particle dynamics from molecular dynamics. The rules of the dissipative particle dynamics are derived from the underlying molecular interactions, and a Langevin equation is…

Soft Condensed Matter · Physics 2009-10-31 Eirik G. Flekkoy , Peter V. Coveney

Quantum dynamics (i.e., the Schr\"odinger equation) and classical dynamics (i.e., Hamilton equations) can both be formulated in equal geometric terms: a Poisson bracket defined on a manifold. In this paper we first show that the hybrid…

Chemical Physics · Physics 2013-06-21 J. L. Alonso , A. Castro , J. Clemente-Gallardo , J. C. Cuchí , P. Echenique , F. Falceto

A theoretical model is introduced for constructing the vibrational Hamiltonian of Hydrogen-like atoms (HLA). The Hamiltonian is then used to derive the vibrational motion equations of HLA in Heisenberg picture. The Langevin equation will…

Quantum Physics · Physics 2020-03-26 J. Jahanpanah

The physical significance of the stochastic processes associated to the generalized Gibbs ensembles is scrutinized here with special attention to the thermodynamic fluctuations of small systems. The contact with the environment produces an…

Statistical Mechanics · Physics 2024-09-04 Amilcare Porporato , Salvatore Calabrese , Lamberto Rondoni

We consider the extreme value statistics of correlated random variables that arise from a Langevin equation. Recently, it was shown that the extreme values of the Ornstein-Uhlenbeck process follow a different distribution than those…

Statistical Mechanics · Physics 2021-08-17 Lior Zarfaty , Eli Barkai , David A. Kessler

We consider numerical methods for thermodynamic sampling, i.e. computing sequences of points distributed according to the Gibbs-Boltzmann distribution, using Langevin dynamics and overdamped Langevin dynamics (Brownian dynamics). A wide…

Statistical Mechanics · Physics 2015-01-13 Benedict Leimkuhler , Charles Matthews , Gabriel Stoltz

We look at the equilibrium of a Brownian particle in an inhomogeneous space following the alternative approach proposed in ref.[1]. We consider a coordinate dependent damping that makes the stochastic dynamics the one with multiplicative…

Statistical Mechanics · Physics 2014-10-07 Avik Biswas , A. Bhattacharyay