COMPUTER SIMULATION OF DIFFUSION PROCESSES IN TILT SPATIO-PERIODIC POTENTIALS

Abstract

It was recently shown that in essentially nonequilibrium systems, the diffusion coefficient can behave nonmonotonically with temperature. One example of such systems with anomalous temperature dependence is the motion of Brownian particles in spatially periodic structures. The aim of the article was to study the change in the temperature dependence of diffusion in underdamped systems with a low coefficient of friction. In this paper, computer simulation methods are used to study the change in the diffusion coefficient of particles in a wide range of temperatures in oblique spatially periodic potentials for different values of the friction coefficient. It is shown that diffusion reaches a maximum at a certain external force. Its value depends on the coefficient of friction. It is shown that, in contrast to the usual Arrhenius dependence, in the case of an inclined periodic potential, the maximum diffusion coefficient increases while temperature is decreasing exponentially. It is established that such a dependence is common to all underdamped systems. It is shown that for spatially periodic structures there is a limited portion of forces in which an increase in the diffusion coefficient while decreasing temperature is observed. This is the area of the so-called temperature-anomalous diffusion (TAD). The width and position of the TAD region are determined depending on the friction coefficient and the system parameters. It has been shown that a decrease in , width TAD region decreases proportionally . In this case, the diffusion coefficient in the TAD region, on the contrary, increases . The data obtained on the temperature and the anomalous diffusion are important for various fields of physics and engineering, and opens new prospects for a diffusion process control technology.