title: Beliaev damping of quasiparticles in a Bose-Einstein condensate.
abstract: We report a measurement of the suppression of collisions of quasiparticles with ground state atoms within a Bose-Einstein condensate at low momentum. These collisions correspond to Beliaev damping of the excitations, in the previously unexplored regime of the continuous quasiparticle energy spectrum. We use a hydrodynamic simulation of the expansion dynamics, with the Beliaev damping cross section, in order to confirm the assumptions of our analysis.
authors.affiliation: Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: N
authors.initials: N
authors.lastname: Katz
authors.forename: J
authors.initials: J
authors.lastname: Steinhauer
authors.forename: R
authors.initials: R
authors.lastname: Ozeri
authors.forename: N
authors.initials: N
authors.lastname: Davidson