Negative quantum friction in nanoscale water flows: the Wigner picture

We explore the phenomenon of "quantum" friction based on a single-particle model patterned after the Wigner equation describing electrons flow in a solid wall confining nanoscale water flows. The numerical simulations show a clear signature of negative quantum friction, namely a net momentum transfer from the electrons in the solid wall to the flowing water molecules. Such net momentum transfer results into a sizeable reduction of the water friction, up to forty percent, depending on the strength of the coupling between classical and quantum fluctuations. Our results offer the prospect of a theoretical framework bridging classical and quantum description by using continuum kinetic theories and particle-based simulations.