SKM 2021 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 9: Poster Session: Correlated Electrons

TT 9.40: Poster

Dienstag, 28. September 2021, 13:30–16:00, P

Quantum friction in the hydrodynamic model — •Kunmin Wu, Thomas Schmidt, and María Farias — Campus Limpertsberg, University of Luxembourg Faculty of Science, Technology and Medicine 162 A, avenue de la Faïencerie L-1511 Luxembourg

We study the phenomenon of quantum friction in a system consisting of a polarizable atom moving at a constant speed parallel to a metallic plate. The plate is described using a charged hydrodynamic model for the electrons. This model featuring long-range, instantaneous interactions is appropriate for graphene or a clean metal in a temperature range where scattering due to Coulomb interactions dominates over the scattering of electron by impurities. We find that a quantum friction force between the atom and the metal surface exists even in the absence of intrinsic damping in the plate, but that it only starts once the velocity of the atom exceeds the effective speed of sound in the plate. We argue that this condition can be fulfilled most easily in metals with nearly empty or nearly filled bands. We make quantitative predictions for the friction force to the second and fourth order in the atomic polarizability, and show that the threshold behavior persists to all orders of the perturbation theory.