Heidelberg 2015 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

Q: Fachverband Quantenoptik und Photonik

Q 19: Quantum Gases: Fermions III

Q 19.1: Vortrag

Dienstag, 24. März 2015, 11:00–11:15, K/HS2

Exploring the Ionic-Hubbard model with ultracold fermions — •Michael Messer, Gregor Jotzu, Rémi Desbuquois, Thomas Uehlinger, Frederik Görg, Daniel Greif, Sebastian Huber, and Tilman Esslinger — ETH Zurich, 8093 Zurich, Switzerland

The Ionic Hubbard model is a fundamental model that describes the competition between different density-ordered phases, which originate from the interplay of the underlying geometry and inter-particle interactions. Depending on the energy scales, it can feature a charge-density-wave ordered state or a Mott-insulating state.

In our experiment we realize the Ionic Hubbard model on a honeycomb lattice by loading a two-component interacting Fermi gas into an optical lattice with a staggered energy offset on alternating sites. We characterize the state of the system by performing noise correlation measurements of the atomic momentum distribution. For large energy offsets we observe a staggered density ordered state, which is suppressed when increasing the repulsive on-site interactions. We additionally characterize the staggered density order by measuring the double occupancy as a function of interaction and energy offset. Furthermore, we explore the distinct response of the charge excitation spectrum for different strengths of the energy offset using lattice modulation spectroscopy and find gapped excitation spectra in the Mott-insulating regime.