In this paper, we develop a multiscale approach to model intrinsic dissipation under high frequency of vibrations in solids. For vibrations with a timescale comparable to the phonon relaxation time, the local phonon distribution deviates from the equilibrium distribution. We extend the quasiharmonic (QHM) method to describe the dynamics under such a condition. The local deviation from the equil...

We develop an efficient sampling method by simulating Langevin dynamics with an artificial force rather than a natural force by using the gradient of the potential energy. The standard technique for sampling following the predetermined distribution such as the GibbsBoltzmann one is performed under the detailed balance condition. In the present study, we propose a modified Langevin dynamics viol...

We study the deterministic and stochastic rotational dynamics of ferromagnetic nanoparticles in a precessing magnetic field. Our approach is based on the system of effective Langevin equations and on the corresponding Fokker-Planck equation. Two key characteristics of the rotational dynamics, namely the average angular frequency of precession of nanoparticles and their average magnetization, ar...

Carbon chains are produced from a graphite (0 0 0 1) surface due to hydrogen atom sputtering. The carbon chains do chemical reaction with hydrogen ion in edge plasma. In this paper, the chemical reaction of the carbon chains in the hydrogen atom gas, which substitutes for hydrogen plasma, was investigated by the use of molecular dynamics simulation with modified Brenner reactive empirical bond ...

We perform numerical simulations of a model micromachine driven by catalytic chemical reactions. Our includes mechano-chemical coupling between the structural variables and nonequilibrium variable describing The time-correlation functions are calculated further analyzed in terms odd Langevin dynamics. obtain effective elastic constant that manifests broken time-reversal symmetry micromachine. W...

Path reweighting is a principally exact method to estimate dynamic properties from biased simulations—provided that the path probability ratio matches stochastic integrator used in simulation. Previously reported ratios match Euler–Maruyama scheme for overdamped Langevin dynamics. Since molecular dynamics simulations use rather than dynamics, this severely impedes application of methods. Here, ...

Markov chains and diffusion processes are indispensable tools in machine learning and statistics that are used for inference, sampling, and modeling. With the growth of large-scale datasets, the computational cost associated with simulating these stochastic processes can be considerable, and many algorithms have been proposed to approximate the underlying Markov chain or diffusion. A fundamenta...

The Langevin thermostat does not reproduce the correct hydrodynamics, i.e., the hydrodynamic interactions are unphysically screened. To correctly describe hydrodynamic interactions, we have to use the DPD thermostat1,2 instead. The DPD thermostat satisfies Newton’s third law by construction and owing to mass, momentum and temperature conservation, hydrodynamics is also properly reproduced.3 We ...