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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 11: Brownian Motion and Transport (joint session DY, CPP)
CPP 11.4: Vortrag
Montag, 16. März 2015, 16:00–16:15, BH-N 243
Hydrodynamically enforced entropic trapping of Brownian particles — •Steffen Martens1, Arthur Straube2, Gerhard Schmid3, Lutz Schimansky-Geier2, and Peter Hänggi3 — 1Technische Universität Berlin, Berlin, Germany — 2Humboldt-Universität zu Berlin, Berlin, Germany — 3Universität Augsburg, Augsburg, Germany
In small systems spatial confinement causes entropic forces that in turn implies spectacular consequences for the control for mass and charge transport. Therefore, recent efforts in theory triggered activities which allow for an approximate description that involves a reduction of dimensionality. Up to present days, the focus was on the role of conservative forces and its interplay with confinement. Within the presented work, we overcome this limitation and succeeded in considering also ”magnetic field” like, so termed non-conservative forces that derive from a vector potential [S. Martens et al., Phys. Rev. Lett. 110, 010601 (2013)]. A relevant application is the fluid flow across microfluidic structures where a solute of Brownian particles is subject to both, an external bias and a pressure-driven flow. Then a new phenomenon emerges; namely, the intriguing finding of identically vanishing average particle flow which is accompanied by a colossal suppression of diffusion [S. Martens et al., arXiv:1407.5673]. This entropy-induced phenomenon, which we termed hydrodynamically enforced entropic trapping, offers the unique opportunity to separate particles of the same size in a tunable manner [S. Martens et al.,Eur. Phys. J. ST 222, 2453-2463 (2013)].