title: Unconventional Superfluidity in Yttrium Iron Garnet Films.
abstract: We argue that the magnon condensate in yttrium iron garnet may display experimentally observable superfluidity at room temperature despite the 100 times dominance of the normal density over superfluid ones. The superfluidity has a more complicated nature than in known superfluids since the U(1) symmetry of the global phase shift is violated by the dipolar interaction leading to the exchange of spin moment between the condensate and the crystal lattice. It produces periodic inhomogeneity in the stationary superfluid flow. We discuss the manner of observation and possible applications of magnon superfluidity. It may strongly enhance the spin-torque effects and reduce the energy consumption of the magnonic devices.
authors.affiliation: Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Sun
authors.affiliation: Institute für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77a, D-50937 Köln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nattermann
authors.affiliation: Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA and Landau Institute for Theoretical Physics, Chernogolovka, Moscow District 142432, Russia.
authors.forename: Valery L
authors.initials: VL
authors.lastname: Pokrovsky