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Q: Fachverband Quantenoptik und Photonik

Q 65: Quantum Gases : Lattices III

Q 65.3: Vortrag

Freitag, 12. März 2010, 14:45–15:00, E 001

Quantitative temperature determination of ultracold fermions in an optical lattice — •Thomas Uehlinger¹, Robert Jördens¹, Daniel Greif¹, Niels Strohmaier¹, Leticia Tarruell¹, Henning Moritz¹, Tilman Esslinger¹, Lorenzo De Leo², Corinna Kollath², Antoine Georges^2,3, Vito Scarola⁴, Lode Pollet⁵, Evgeni Burovski⁶, Evgeny Kozik⁷, and Matthias Troyer⁷ — ¹Institute for Quantum Electronics, ETH Zurich, 8093 Zurich, Switzerland — ²Centre de Physique Théorique, CNRS, Ecole Polytechnique, 91128 Palaiseau, France — ³Collège de France, 11 place Marcelin Berthelot, 75231 Paris, France — ⁴Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA — ⁵Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA — ⁶Laboratoire de Physique Théorique et Modèles Statistiques, Université Paris-Sud, 91405 Orsay, France — ⁷Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland

While experiments with ultracold fermions in optical lattices are approaching magnetically ordered states of the Fermi Hubbard model, a reliable determination of temperature in the regime of intermediate interaction has yet not been possible. We compare precise measurements of the double occupancy in our system with both DMFT calculations and the high-temperature series expansion. Both methods agree with the experimental data over a wide range of parameters. The entropy per atom in the center of the trap is about twice as large as the entropy required to enter the Néel phase. The corresponding temperature reaches values on the order of the tunneling energy t.