| Molecular mechanism underlying enhanced dynamics in heterogeneous envirounments |
We have investigated molecular mechanism underlying enhanced dynamics in heterogeneous environments.
Enhanced particle diffusion in fluctuating binary environments
We investigate single-particle diffusion in a two-state Langevin model where the friction coefficient randomly switches between low-friction (liquid-like) and high-friction (glassy-like) states. The dynamics are governed by the ratio between the friction switching time τ and the intrinsic velocity relaxation time τ0. For fast switching (τ/τ0 <~ 1) the motion is homogeneous and Brownian, whereas for slow switching (τ/τ0 >> 1) the particle exhibits intermittent dynamics and an enhanced diffusion coefficient. Analysis of the single-particle overlap function Q(t) and the dynamic susceptibility χ4(t) reveals decoupling of the diffusion coefficient from the average friction upon cooling, which coincides with increasing temporal dynamic heterogeneity. This minimal model provides a transparent framework for understanding single-particle transport in media with temporally fluctuating local mobility and intermittent fast/slow dynamical regimes.
Perakis, Kawasaki, & Saito, Phys. Rev. Res. (2026).
