  We propose and study a quantum pump which emulates a traditional paddlewheel,
that can be implemented with ultracold atoms in waveguides. We use wavepacket
propagation to study its single-mode dynamics, which also determines its
multimode current for mesoscopic setups. Energy flow with or without particle
transport is possible. The spectrum reveals unusual features such as nonuniform
Floquet side-bands and counter-intuitive scattering. Explanations are found by
examining the scattering dynamics comparatively using quantum, classical and
semiclassical pictures, indicating a rich system and experimentally accessible
method to explore quantum versus classical dynamics.

Quantum Gases