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PRODID:-//University of Illinois//Web Services Calendar//EN
VERSION:2.0
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BEGIN:VEVENT
DTSTAMP:20120214T140659Z
DTSTART;TZID=America/Chicago:20091113T130000
DTEND;TZID=America/Chicago:20091113T130000
SUMMARY:Condensed Matter Seminar: Observation of Fermi Polarons in a tuna
 ble Fermi liquid of ultracold atoms
CREATED:20090825T130000Z
DESCRIPTION:Abstract:We have observed Fermi polarons in a highly imbalanc
 ed mixture of fermionic atoms using tomographic RF spectroscopy. Feshbac
 h resonances allow to freely tune the interactions between the two spin 
 states involved. A single spin down atom immersed in a Fermi sea of spin
  up atoms can do one of two things:For strong attraction\, it can form a
  molecule with exactly one spin up partner\, but for weaker interaction 
 it will spread its attraction and surround itself with a collection of m
 ajority atoms. This spin down atom "dressed" with a spin up cloud consti
 tutes the Fermi polaron. We have observed a striking spectroscopic signa
 ture of this quasi-particle for various interaction strengths\, which al
 lows us to directly measure the polaron energy and infer the quasi-parti
 cle residue Z.The polarons are weakly interacting\, and can thus be iden
 tified with the quasi-particles of Landau's Fermi liquid theory.At a cri
 tical interaction strength\, the quasi-particle residue Z vanishes\, ind
 icating a transition from polarons to molecules. At this point the Fermi
  liquid of polarons undergoes a phase transition into a superfluid Bose 
 liquid.
LAST-MODIFIED:20091013T130000Z
LOCATION:190 Engineering Sciences Building\, 1101 W. Springfield\, Urbana
 
CATEGORIES:CM Seminar
CONTACT:Peggy Pennell 244-7636
ORGANIZER:ppennell@illinois.edu
URL:http://illinois.edu/calendar/detail/1968?key=2000010120000101133319
UID:133319@illinois.edu
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