A quantum pump without a crank

Pumps, in a nutshell, are devices that use cyclic motion to attain the steady transport of some cargo. In a bicycle pump, the repeated up and down strokes of a piston create air flow. In a Archimedean screw pump, water is transferred between reservoirs by turning a crank. Related concepts have been explored as well in quantum systems, in particular for transporting electrons one by one through solid-state materials, thereby generating a quantized current.