Quantum Paddlewheel with Ultracold Atoms in Waveguides

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.