Berlin 2012 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Brownian Motion and Transport

DY 25.13: Topical Talk

Thursday, March 29, 2012, 13:00–13:30, MA 004

Transport beyond Brownian Motion – Persistent correlations — •Thomas Franosch — Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

Brownian motion is one of the pillars of statistical physics with applications ranging from astrophysics to biological physics. The theoretical foundation is well understood since Einstein and Smoluchowski introduced a probabilistic interpretation to derive diffusion as a macroscopic law. In modern language, the diffusion propagator follows from the central limit theorem.

Although the mean-square displacement is dominated by the linear increase for long times and finite diffusion constant, persistent correlation underlying the transport may be unraveled by studying the corresponding velocity autocorrelation functions (VACF). I will discuss recent theoretical, simulation, and experimental advances highlighting power-law tails in the VACF which correspond to a colored component in the power spectrum of the force correlator. In particular, I will focus on the effects of hydrodynamic backflow [1,2] and the repeated scattering from frozen obstacles [3,4] as paradigmatic mechanisms to generate persistent correlations.

[1] T. Franosch et al., Nature 478, 85-88 (2011)

[2] S. Jeney et al., Phys. Rev. Lett. 100, 240604 (2008)

[3] F. Höfling and T. Franosch, Phys. Rev. Lett. 98, 140601, (2007)

[4] T. Franosch et al., Chem. Phys. 375, 530 (2010)