Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 17: Fermi Quantum Gas
Q 17.3: Vortrag
Dienstag, 15. März 2011, 11:00–11:15, BAR Schön
Local observation of density and fluctuations in a trapped Fermi gas — •David Stadler1, Torben Müller1, Bruno Zimmermann1, Jakob Meineke1, Jean-Philippe Brantut1, Henning Moritz2, and Tilman Esslinger1 — 1Institut für Quantenelektronik, ETH Zürich, Schweiz — 2Institut für Laser-Physik, Universität Hamburg, Deutschland
We present in-situ observations of density and density fluctuations in a two-component Fermi gas of Lithium atoms.
These observations are performed in an apparatus, which features two microscope objectives, allowing high-resolution (about 1 micrometer) in-situ optical detection of the cloud. By measuring the number of atoms in small regions of the cloud on many realisations of the experiment, we locally measure the mean and the variance of the atomic density. For a non-degenerate, weakly interacting gas, we observe density fluctuations proportional to the mean cloud density (atomic shot-noise), in agreement with classical statistics. In a degenerate, weakly interacting fermi gas, we observe a strong reduction of density fluctuations compared to the classical limit. This represents a direct manifestation of Fermi-Dirac statistics, complementary to the Hanbury-Brown and Twiss observations performed with cold atoms after time-of-flight.
In addition we present an interferometric detection scheme that allows to extend fluctuation measurements to the magnetic properties of a two-component Fermi gas.