title: Asymmetric drag in oscillatory motion: ratchet effect without an asymmetric potential.
abstract: Asymmetry of magnetic objects in a fluid under an oscillating magnetic field leads to a wealth of nonequilibrium dynamics phenomena including a novel ratchet effect without an asymmetric substrate. These nonlinear dynamics are explained in the framework of the Stokes' model by a drag coefficient, which depends on the direction of motion. This approach is general and is independent of the physical mechanism responsible for this directional dependence of the drag coefficient as well as the size of the object. The theoretical model is experimentally verified for two systems, a nonrigid magnetic microcoil and a chiral magnetic macroobject immersed in a bounded fluid.
authors.affiliation: Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany. v.fomin@ifw-dresden.de
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Fomin
authors.forename: Elliot J
authors.initials: EJ
authors.lastname: Smith
authors.forename: Dmitriy D
authors.initials: DD
authors.lastname: Karnaushenko
authors.forename: Denys
authors.initials: D
authors.lastname: Makarov
authors.forename: Oliver G
authors.initials: OG
authors.lastname: Schmidt
mesh_terms: D003198:Computer Simulation; D017276:Friction / Q000528:radiation effects; D060526:Magnetic Fields; D008956:Models, Chemical; D008958:Models, Molecular; D012212:Rheology / Q000379:methods*; D012996:Solutions / Q000737:chemistry* / Q000528:radiation effects*; D014783:Viscosity / Q000528:radiation effects
chemical_list: D012996:Solutions