Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 69: Poster: Quantum Systems

DY 69.14: Poster

Donnerstag, 15. März 2018, 15:30–18:00, Poster A

Non-universal behaviour in branched flow — •Philipp Breul and Ragnar Fleischmann — Max-Planck-Institut für Dynamik und Selbstorganisation, Göttingen

When waves propagate in a weakly scattering complex medium they are strongly focused into branch-like structures on length scales much shorter than the mean-free-path. This branched flow is a very general phenomenon: wind driven ocean waves, light, sound, conduction electrons, tsunamis and even earth quakes are examples of waves that in a natural environment typically propagate through a complex medium and can exhibit branching.
Often the medium is best described as a Gaussian random field with intrinsic correlations. For a wide range of different functional forms of these correlations the statistics of branched flows have been found to show universal behaviour that only depends on a few characteristic quantities like the variance σ² and the integral correlation length ℓ_c of the fluctuations in the medium. For example does the typical length scale ℓ_b of branched flows scale like σ^−2/3. Inspired by the statistical structure of two-dimensional turbulent fields we study branched flows in media with pronounced anti-correlations that lead to vanishing integral correlation length in transverse direction to the flow. We find that such media exhibit strongly non-universal behaviour and the branchinglength scales like ℓ_b ∼ σ⁻¹.