Anomalous transport in heterogeneous media

The diffusion dynamics of particles in heterogeneous media is studied using particle-based simulation techniques. A special focus is placed on systems where the transport of particles at long times exhibits anomalies such as subdiffusive or superdiffusive behavior. First, a two-dimensional model sys...

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Bibliographic Details
Published inThe European physical journal. ST, Special topics Vol. 226; no. 14; pp. 3113 - 3128
Main Authors Horbach, Jürgen, Siboni, Nima H., Schnyder, Simon K.
Format Journal Article
LanguageEnglish
Published Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2017
Springer Nature B.V
Subjects
Anomalies
Atomic
Classical and Continuum Physics
Computer simulation
Condensed Matter Physics
Glass formation
Lorentz gas
Materials Science
Measurement Science and Instrumentation
Molecular
Nonlinear Response to Probe Vitrification
Optical and Plasma Physics
Physics
Physics and Astronomy
Review
Rheological properties
Rheology
Tracer particles
Tracers
Transport
Two dimensional models
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Summary:The diffusion dynamics of particles in heterogeneous media is studied using particle-based simulation techniques. A special focus is placed on systems where the transport of particles at long times exhibits anomalies such as subdiffusive or superdiffusive behavior. First, a two-dimensional model system is considered containing gas particles (tracers) that diffuse through a random arrangement of pinned, disk-shaped particles. This system is similar to a classical Lorentz gas. However, different from the original Lorentz model, soft instead of hard interactions are considered and we also discuss the case where the tracer particles interact with each other. We show that the modification from hard to soft interactions strongly affects anomalous-diffusive transport at high obstacle densities. Second, non-linear active micro-rheology in a glass-forming binary Yukawa mixture is investigated, pulling single particles through a deeply supercooled state by applying a constant force. Here, we observe superdiffusion in force direction and analyze its origin. Finally, we consider the Brownian dynamics of a particle which is pulled through a two-dimensional random force field. We discuss the similarities of this model with the Lorentz gas as well as active micro-rheology in glass-forming systems.
ISSN:1951-6355
1951-6401
DOI:10.1140/epjst/e2017-70081-3