Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 11: Brownian Motion and Transport (joint session DY, CPP)

CPP 11.9: Talk

Monday, March 16, 2015, 17:30–17:45, BH-N 243

Enhancement of mobility in a feedback controlled 1D colloidal system with repulsive interactions — •Robert Gernert and Sabine H. L. Klapp — Institut für theoretische Physik, Technische Universität Berlin

Feedback control schemes are a promising way to design static and dynamic properties of colloidal suspensions [1]. In the collective transport of colloids through 1D tilted washboard potentials clusters of attractive particles are known to overcome the hindering influence of the potential barriers [2]. Here we consider a corresponding system with repulsive interactions. To enhance the mobility we propose a feedback control scheme and demonstrate its function theoretically. The control is modelled by a symmetrically confining potential, like an optical tweezer, and it is always centered around the mean particle position. For the theoretical demonstration we use Dynamical Density Functional Theory (DDFT) with ultra-soft as well as hard-core particle interactions. For either type of interaction the influence of the hindering washboard potential can be suppressed completely – corresponding to an enhancement of the mobility by several orders of magnitude. Further, in the regime of moderate amplification velocity oscillations are induced.

[1] B. Qian, D. Montiel, A. Bregull, F. Cichos, and H. Yang, Chem. Sci. 4, 1420 (2013)

[2] M. Evstigneev, S. von Gehlen, and P. Reimann, PRE 79, 011116 (2009)