Dynamics in a Fermi lattice gas

Ultracoldfermionicatomstrappedinopticallatticesprovideaplatformtostudyphenomenainstronglycorrelatedsystemsthatareotherwisechallengingtoprobeincondensedmatter.Inthistalk,afteranintroductiontotheideaofusingultracoldatomicquantumsimulation,Iwilldiscussourdiscoveryof"badmetal"behaviorforthefirsttimeinquantumgases.Badmetals,suchasthenormalstateofsomehigh-temperaturesuperconductors,presentanomalousscalingofresistivitywithtemperatureandtheabsenceofwell-definedquasiparticles.Acompleteunderstandingofbadmetalbehaviorremainsdebated.Inourgroup,wedirectlymeasurethetransportlifetimeinducedbyinter-particlescatteringforamasscurrentofatomsexcitedbystimulatedRamantransitionsandinfertheanalogofresistivity.Byexploringarangeofinteractionstrengthsandaregimeoftemperatureinaccessibletosolids,weidentifytwocharacteristicsofbadmetals,T-linearresistivityandincoherenttransport.Therelationshipbetweenanomalousresistivityscaling,areductionofquasiparticleweightfromstronginteractions,andbad-metalbehaviorisvalidatedthroughcomparisontodynamicalmean-fieldtheory(DMFT)simulations.Iftimeisallowed,IwillalsopresentourrecentresultsonintroducingcorrelatedtunnelingintoFermiHubbardmodel,whichallowsthefuturestudyonphenomenainvolvingdensity-dependentgaugefield.