Heimsoth, M.Creffield, CharlesSols Lucía, Fernando2023-06-202023-06-202010-08-121050-294710.1103/PhysRevA.82.023607https://hdl.handle.net/20.500.14352/44731©2010 The American Physical Society. This work was supported by MICINN (Spain), through Grant No. FIS-2007-65723 and the Ramón y Cajal Program (CEC).We present an analytical study of the response of cold atoms in an optical lattice to a weak time- and space-asymmetric periodic driving signal. In the noninteracting limit, and for a finite set of resonant frequencies, we show how a coherent, long-lasting ratchet current results from the interference between first- and second-order processes. In those cases, a suitable three- level model can account for the entire dynamics, yielding surprisingly good agreement with numerically exact results for weak and moderately strong driving.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.82.023607http://journals.aps.orgopen access538.9Brownian motorsTransportFísica de materialesFísica del estado sólido2211 Física del Estado Sólido