# Stuttgart 2012 – wissenschaftliches Programm

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# Q: Fachverband Quantenoptik und Photonik

## Q 21: Quantengase: Optische Gitter 1

### Q 21.2: Vortrag

### Dienstag, 13. März 2012, 10:45–11:00, V53.01

**Dynamics of ultracold fermions in higher lattice orbitals** — •Nick Fläschner, Jannes Heinze, Jasper Simon Krauser, Sören Götze, Christoph Becker, and Klaus Sengstock — Universität Hamburg, Institut für Laser-Physik, Luruper Chaussee 149, 22761 Hamburg, Germany

Due to the analogy to electrons in crystals, ultracold fermions in optical lattices are ideally suited to simulate solid-state systems. These are often characterized by their dynamical response to an external perturbation, e.g. charge transport in electric fields. To compare both situations, it is highly interesting to investigate the dynamical properties of ultracold fermions in optical lattices. For this, we prepare spin-polarized fermions in a shallow 1D-lattice, excite a small fraction to the third band using lattice amplitude modulation and thus create particle-hole pairs with a well-defined momentum [1]. We observe the time evolution of the particle-hole pair in momentum space which reveals an oscillatory behavior. The oscillation frequency is dependent on the initial momentum of the excitations, the trapping frequency of the harmonic confinement and the lattice depth. We compare our data to a single-particle quantum model yielding very good quantitative agreement. Our findings will allow us to investigate the dynamical properties of interacting Fermi spin-mixtures as well as transport properties of fermionic quantum gases in higher bands.