title: Cooling of a Bose-Einstein Condensate by Spin Distillation.
abstract: We propose and experimentally demonstrate a new cooling mechanism leading to purification of a Bose-Einstein condensate (BEC). Our scheme starts with a BEC polarized in the lowest energy spin state. Spin excited states are thermally populated by lowering the single particle energy gap set by the magnetic field. Then, these spin-excited thermal components are filtered out, which leads to an increase of the BEC fraction. We experimentally demonstrate such cooling for a spin 3 ^{52}Cr dipolar BEC. Our scheme should be applicable to Na or Rb, with the perspective to reach temperatures below 1 nK.
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: B
authors.initials: B
authors.lastname: Naylor
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: E
authors.initials: E
authors.lastname: Maréchal
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|Department of Physics and Engineering Technology, Bloomsburg University of Pennsylvania, Bloomsburg, Pennsylvania 17815, USA.
authors.forename: J
authors.initials: J
authors.lastname: Huckans
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: O
authors.initials: O
authors.lastname: Gorceix
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: P
authors.initials: P
authors.lastname: Pedri
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: L
authors.initials: L
authors.lastname: Vernac
authors.affiliation: Université Paris 13, Sorbonne Paris Cité, Laboratoire de Physique des Lasers, F-93430 Villetaneuse, France.|CNRS, UMR 7538, LPL, F-93430 Villetaneuse, France.
authors.forename: B
authors.initials: B
authors.lastname: Laburthe-Tolra