Friday, March 8, 2013

1303.1702 (Mario Heidernätsch et al.)

Characterizing N-dimensional anisotropic Brownian motion by the
distribution of diffusivities
   [PDF]

Mario Heidernätsch, Michael Bauer, Günter Radons
Anisotropic diffusion processes emerge in various fields such as transport in biological tissue and diffusion in liquid crystals. In such systems, the motion is described by a diffusion tensor. For a proper characterization of processes with more than one diffusion coefficient an average description by the mean squared displacement is often not sufficient. Hence, in this paper, we use the distribution of diffusivities to study diffusion in a homogeneous anisotropic environment. We derive analytical expressions of the distribution and relate its properties to an anisotropy measure in order to distinguish between isotropic and anisotropic processes. We further discuss the influence on the analysis of projected trajectories, which are typically accessible in experiments. For the experimentally relevant cases of two- and three-dimensional anisotropic diffusion we derive the specific expressions, determine the diffusion tensor, characterize the anisotropy, and demonstrate the applicability for simulated trajectories.
View original: http://arxiv.org/abs/1303.1702

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