title: Observation of anomalous spin-state segregation in a trapped ultracold vapor.
abstract: We observe counterintuitive spin segregation in an inhomogeneous sample of ultracold, noncondensed rubidium atoms in a magnetic trap. We use spatially selective microwave spectroscopy to verify a model that accounts for the differential forces on two internal spin states. In any simple understanding of the cloud dynamics, the forces are far too small to account for the dramatic transient spin polarizations observed. The underlying mechanism remains to be elucidated.
authors.affiliation: JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Lewandowski
authors.forename: D M
authors.initials: DM
authors.lastname: Harber
authors.forename: D L
authors.initials: DL
authors.lastname: Whitaker
authors.forename: E A
authors.initials: EA
authors.lastname: Cornell