title: Pumping single-file colloids: Absence of current reversal.
abstract: We consider the single-file motion of colloidal particles interacting via short-range repulsion and placed in a traveling wave potential that varies periodically in time and space. Under suitable driving conditions, a directed time-averaged flow of colloids is generated. We obtain analytic results for the model using a perturbative approach to solve the Fokker-Planck equations. The predictions show good agreement with numerical simulations. We find peaks in the time-averaged directed current as a function of driving frequency, wavelength, and particle density and discuss possible experimental realizations. Surprisingly, unlike a closely related exclusion dynamics on a lattice, the directed current in the present model does not show current reversal with density. A linear response formula relating current response to equilibrium correlations is also proposed.
authors.affiliation: Indian Institute of Technology, Hyderabad, Yeddumailaram 502205, Andhra Pradesh, India.
authors.forename: Debasish
authors.initials: D
authors.lastname: Chaudhuri
authors.affiliation: Department of Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Archishman
authors.initials: A
authors.lastname: Raju
authors.affiliation: International Centre for Theoretical Sciences, TIFR, IISc Campus, Bangalore 560012, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Dhar