Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 46: New Methods and Developments 3: Theory
O 46.2: Talk
Wednesday, September 7, 2022, 15:15–15:30, H6
Quantum feedback at the solid-liquid interface: flow-induced electronic current and negative friction — •Baptiste Coquinot1,2, Lydéric Bocquet1, and Nikita Kavokine2 — 1Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Paris, France — 2Center for Computational Quantum Physics, Flatiron Institute, New York, NY 10010, USA
An electronic current driven through a conductor can induce a current in another conductor through the famous Coulomb drag effect. Similar phenomena have been reported at the interface between a moving fluid and a conductor, but their interpretation has remained elusive. Here, we develop a quantum-mechanical theory of the intertwined fluid and electronic flows, taking advantage of the non-equilibrium Keldysh framework. We predict that a globally neutral liquid can generate an electronic current in the solid wall along which it flows. This hydrodynamic Coulomb drag originates from both direct Coulomb interactions and interactions mediated by the solid's phonons. We derive explicitly the Coulomb drag current in terms of the solid's electronic and phononic properties, as well as the liquid's dielectric response, a result which quantitatively agrees with recent experiments at the liquid-graphene interface. Furthermore, we show that the current generation counteracts momentum transfer from the liquid to the solid, leading to a reduction of the hydrodynamic friction coefficient through a quantum feedback mechanism. Our results provide a roadmap for controlling nanoscale liquid flows at the quantum level, and suggest strategies for designing materials with low hydrodynamic friction.