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SUMMARY:Solid state physics with fermionic atomic quantum gases: engineeri
 ng metals and Mott insulators in an optical lattice - Dr Robert Jordens (E
 TH Zurich)
DTSTART:20100916T130000Z
DTEND:20100916T140000Z
UID:TALK26280@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:Strong interactions between electrons in a solid material lead
  to\nsurprising effects such as the Mott insulator\, where a suppression o
 f\nconductivity occurs due to interactions rather than due to a filled\nBl
 och band. Proximity to the Mott insulating phase is the origin of\nmany in
 triguing phenomena in condensed matter physics\, most notably\nhigh-temper
 ature superconductivity. We experimentally implement the\nFermi-Hubbard mo
 del\, which encompasses the physics of the Mott\ninsulator\, by trapping a
  repulsively interacting two-component Fermi\ngas in an optical lattice.  
 The system is characterized using accurate\nmeasurements of the double occ
 upancy. By comparison with ab initio\ncalculations we determine the entrop
 y of the sample and identify\nmetallic as well as Mott insulating states. 
 The unique control over\nthe creation of double occupancies and the high r
 esolution in\ndetecting them also allow us to study dynamic and non-equili
 brium\nproperties. Starting with a repulsively interacting gas of fermions
 \,\nwe perturb the sample by modulating the lattice depth and monitor the\
 nincrease of doublons with time. The observed behavior is captured by\nlin
 ear response theory and is sensitive to temperature and local spin\norderi
 ng. Additionally\, we measure the lifetime of doublons in the\nisolated ma
 ny-body system. Over two orders of magnitude\, it shows an\nexponential de
 pendence on the ratio of interaction energy to kinetic\nenergy\, in agreem
 ent with diagrammatic calculations
LOCATION:Rutherford building\, Seminar Room B
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