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RESEARCH PRODUCT
Metallic and Insulating Phases of Repulsively Interacting Fermions in a 3D Optical Lattice
R. W. HelmesImmanuel BlochTh. BestAchim RoschSebastian WillLucia HackermüllerUlrich SchneiderT. A. CostiDavid Raschsubject
PhysicsCondensed Matter::Quantum GasesOptical latticeMultidisciplinaryStrongly Correlated Electrons (cond-mat.str-el)Hubbard modelCondensed matter physicsFOS: Physical sciencesFermionsymbols.namesakeCondensed Matter - Strongly Correlated ElectronsMean field theorysymbolsStrongly correlated materialCondensed Matter::Strongly Correlated ElectronsFermi liquid theoryMetal–insulator transitionHamiltonian (quantum mechanics)description
The fermionic Hubbard model plays a fundamental role in the description of strongly correlated materials. Here we report on the realization of this Hamiltonian using a repulsively interacting spin mixture of ultracold $^{40}$K atoms in a 3D optical lattice. We have implemented a new method to directly measure the compressibility of the quantum gas in the trap using in-situ imaging and independent control of external confinement and lattice depth. Together with a comparison to ab-initio Dynamical Mean Field Theory calculations, we show how the system evolves for increasing confinement from a compressible dilute metal over a strongly-interacting Fermi liquid into a band insulating state. For strong interactions, we find evidence for an emergent incompressible Mott insulating phase.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-12-05 |