Brownian Yet Non-Gaussian Diffusion of a Light Particle in Heavy Gas: Lorentz Gas Based Analysis
arXiv:2303.13119 · doi:10.1103/PhysRevE.108.044129
Abstract
Non-Gaussian diffusion was recently observed in gas mixtures with mass and fraction contrast [F. Nakai et al, Phys. Rev. E 107, 014605 (2023)]. The mean square displacement of a minor gas particle with a small mass is linear in time, while the displacement distribution deviates from the Gaussian distribution, which is called the Brownian yet non-Gaussian diffusion. In this work, we theoretically analyze this case where the mass contrast is sufficiently large. Major heavy particles can be interpreted as immobile obstacles, and a minor light particle behaves like a Lorentz gas particle within an intermediate time scale. Despite the similarity between the gas mixture and the conventional Lorentz gas system, the Lorentz gas description cannot fully describe the Brownian yet non-Gaussian diffusion. A successful description can be achieved through an ensemble average of the statistical quantities of the Lorentz gas over the initial speed.
6 pages, 4 figures
References in corpus (10)
- Anomalous transport in the crowded world of biological cells
- Universal nature of particle displacements close to glass and jamming transitions
- Crossover in the Slow Decay of Dynamic Correlations in the Lorentz Model
- Critical dynamics of ballistic and Brownian particles in a heterogeneous environment
- Tagged-particle dynamics in a fluid adsorbed in a disordered porous solid: interplay between the diffusion-localization and liquid-glass transitions
- Length scales in Brownian yet non-Gaussian dynamics
- Time-Dependent Fluctuations and Superdiffusivity in the Driven Lattice Lorentz Gas
- Non-Gaussian diffusion near surfaces
- Dynamic heterogeneities and non-Gaussian behavior in two-dimensional randomly confined colloidal fluids
- Fluctuating Diffusivity Emerges even in Binary Gas Mixtures