arXiv subjects

V. Aksenova

Publications and source records attributed to V. Aksenova.

3 recordsLinked to original sources

arXiv2025

Giant increase of diffusion by small rise of friction

Diffusion coefficient usually decreases when friction increases. We analyze the opposite behavior in the paradigmatic system consisting of an inertial Brownian particle moving in a symmetric spatially periodic potential and driven by an unbiased time periodic force. For tailored parameter set in strong dissipation regime the particle spreading can be giantly amplified: if the friction is twice as large then the diffusion grows up to five orders of magnitude. The mechanism lying behind this effect is related to bifurcation of periodic orbits oscillating around the potential maximum and their symmetric displacement towards the adjacent potential minima when the friction coefficient increases. On the other hand, in the weak dissipation regime, where the increase of diffusion vs friction is also observed, the effect is induced by a non-monotonic change of population of the running orbits. However, in this regime the enhancement of diffusion is much smaller.

cond-mat.stat-mech↗

arXiv2023

Temperature anomalies of oscillating diffusion in ac-driven periodic systems

We analyse the impact of temperature on the diffusion coefficient of an inertial Brownian particle moving in a symmetric periodic potential and driven by a symmetric time-periodic force. Recent studies have revealed the low friction regime in which the diffusion coefficient shows giant damped quasi-periodic oscillations as a function of the amplitude of the time-periodic force [I. G. Marchenko et al., Chaos 32, 113106 (2022)]. We find out that when temperature grows the diffusion coefficient increases at its minima, however, it decreases at the maxima within a finite temperature window. This curious behavior is explained in terms of the deterministic dynamics perturbed by thermal fluctuations and mean residence time of the particle in the locked and running trajectories. We demonstrate that temperature dependence of the diffusion coefficient can be accurately reconstructed from the stationary probability to occupy the running trajectories.

cond-mat.stat-mech↗

arXiv2022

Giant oscillations of diffusion in ac-driven periodic systems

We revisit the problem of diffusion in a driven system consisting of an inertial Brownian particle moving in a symmetric periodic potential and subjected to a symmetric time-periodic force. We reveal parameter domains in which diffusion is normal in the long time limit and exhibits intriguing giant damped quasiperiodic oscillations as a function of the external driving amplitude. As the mechanism behind this effect we identify the corresponding oscillations of difference in the number of locked and running trajectories which carries the leading contribution to the diffusion coefficient. Our findings can be verified experimentally in a multitude of physical systems including colloidal particles, Josephson junction or cold atoms dwelling in optical lattices, to name only a few.

cond-mat.stat-mech↗