Transport and Fractionation in Periodic Potential-Energy Landscapes

Matthew Pelton [1], Kosta Ladavac [1] and David G. Grier [2]
[1] Department of Physics and James Franck Institute
The University of Chicago, Chicago, IL 60637
[2] Department of Physics and Center for Soft Matter Research
New York University, New York, NY 10003

Date: July 10, 2004

Abstract:

Objects driven through periodically modulated potential-energy landscapes in two dimensions can become locked in to symmetry-selected directions that are independent of the driving force's orientation. We investigate this problem in the overdamped limit, and demonstrate that the crossover from free-flowing to locked-in transport can depend exponentially on an object's size, with this exceptional selectivity emerging from the periodicity of the environment.