title: Higher-than-ballistic conduction of viscous electron flows.
abstract: Strongly interacting electrons can move in a neatly coordinated way, reminiscent of the movement of viscous fluids. Here, we show that in viscous flows, interactions facilitate transport, allowing conductance to exceed the fundamental Landauer's ballistic limit [Formula: see text] The effect is particularly striking for the flow through a viscous point contact, a constriction exhibiting the quantum mechanical ballistic transport at [Formula: see text] but governed by electron hydrodynamics at elevated temperatures. We develop a theory of the ballistic-to-viscous crossover using an approach based on quasi-hydrodynamic variables. Conductance is found to obey an additive relation [Formula: see text], where the viscous contribution [Formula: see text] dominates over [Formula: see text] in the hydrodynamic limit. The superballistic, low-dissipation transport is a generic feature of viscous electronics.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Haoyu
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139.
authors.forename: Ekin
authors.initials: E
authors.lastname: Ilseven
authors.affiliation: Department of Physics, Weizmann Institute of Science, Rehovot 76100, Israel.|Institute for Information Transmission Problems, Moscow 127994, Russia.
authors.forename: Gregory
authors.initials: G
authors.lastname: Falkovich
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139; levitov@mit.edu.
authors.forename: Leonid S
authors.initials: LS
authors.lastname: Levitov
keywords: electron hydrodynamics; graphene; strongly correlated systems