Regensburg 2010 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 33: Nonlinear Dynamics II
DY 33.3: Talk
Friday, March 26, 2010, 11:15–11:30, H46
Directing Brownian Motion on a Periodic Surface by Spontaneous Symmetry Breaking — •David Speer1, Ralf Eichhorn2, and Peter Reimann1 — 1Universität Bielefeld, Fakultät für Physik, 33615 Bielefeld, Germany — 2NORDITA, Roslagstullsbacken 23, 10691 Stockholm, Sweden
We consider an overdamped Brownian particle, exposed to a two-dimensional, square lattice potential and a rectangular ac drive. Depending on the driving amplitude, the linear response to a weak dc force along a lattice symmetry axis consist in a mobility in basically any direction. In particular, motion exactly opposite to the applied dc force may arise. Upon changing the angle of the dc force relatively to the square lattice, the particle motion remains predominantly opposite to the dc force. The basic physical mechanism consists in a spontaneous symmetry breaking of the unbiased deterministic particle dynamics [1].
[1] D. Speer et al, Phys. Rev. Lett. 102, 124101 (2009)