47 research outputs found
Relaxation time scales in collective dynamics of liquid alkali metals
In this paper the investigation of the dynamical processes of liquid alkali
metals is executed by analyzing the time scales of relaxation processes in
liquids. The obtained theoretical dynamic structure factor for
the case of liquid lithium is found to be in excellent agreement with the
recently received inelastic X-ray scattering data. The comparison and
interrelation with other theories are given here. Finally, an important part of
this paper is the confirmation of the scale uniformity of the dynamic processes
in liquid alkali metals predicted by some previous molecular dynamic simulation
studies
Universal Approach to Overcoming Nonstationarity, Unsteadiness and Non-Markovity of Stochastic Processes in Complex Systems
In present paper we suggest a new universal approach to study complex systems
by microscopic, mesoscopic and macroscopic methods. We discuss new
possibilities of extracting information on nonstationarity, unsteadiness and
non-Markovity of discrete stochastic processes in complex systems. We consider
statistical properties of the fast, intermediate and slow components of the
investigated processes in complex systems within the framework of microscopic,
mesoscopic and macroscopic approaches separately. Among them theoretical
analysis is carried out by means of local noisy time-dependent parameters and
the conception of a quasi-Brownian particle (QBP) (mesoscopic approach) as well
as the use of wavelet transformation of the initial row time series. As a
concrete example we examine the seismic time series data for strong and weak
earthquakes in Turkey () in detail, as well as technogenic
explosions. We propose a new way of possible solution to the problem of
forecasting strong earthquakes forecasting. Besides we have found out that an
unexpected restoration of the first two local noisy parameters in weak
earthquakes and technogenic explosions is determined by exponential law. In
this paper we have also carried out the comparison and have discussed the
received time dependence of the local parameters for various seismic phenomena
Diffusion Time-Scale Invariance, Markovization Processes and Memory Effects in Lennard-Jones Liquids
We report the results of calculation of diffusion coefficients for
Lennard-Jones liquids, based on the idea of time-scale invariance of relaxation
processes in liquids. The results were compared with the molecular dynamics
data for Lennard-Jones system and a good agreement of our theory with these
data over a wide range of densities and temperatures was obtained. By
calculations of the non-Markovity parameter we have estimated numerically
statistical memory effects of diffusion in detail.Comment: 10 pages, 3 figure
A simple measure of memory for dynamical processes described by the generalized Langevin equation
Memory effects are a key feature in the description of the dynamical systems
governed by the generalized Langevin equation, which presents an exact
reformulation of the equation of motion. A simple measure for the estimation of
memory effects is introduced within the framework of this description.
Numerical calculations of the suggested measure and the analysis of memory
effects are also applied for various model physical systems as well as for the
phenomena of ``long time tails'' and anomalous diffusion