Ruprecht Karls Universität Heidelberg

Condensation in the Quasi-2D BEC-BCS Crossover

last modified on June 09 2015 16:30

Our latest paper was recently published in Physical Review Letters 114, 230401 (also available at arXiv:1409.5373). Here, we investigate a two-dimensional Fermi gas in the BEC-BCS crossover. We measure the pair momentum distribution of the gas by means of our matter wave focusing technique and observe a clear signature for condensation at low temperatures. By tuning the temperature as well as the interaction strength in the gas, we are able to map out the phase diagram of the quasi-2D Fermi gas in the BEC-BCS crossover.
The paper received PRL's "Editors' Suggestion" and was also featured in a nicely written Viewpoint in Physics by Pierbiagio Pieri from the University of Camerino.

More information can be found in the press release from Heidelberg University: English version, German version
The article was also featured on the Facebook page of Physics Today.

Constructing Quantum Matter Atom by Atom

last modified on February 24 2015 14:18

In this publication published in Physical Review Letters ( PRL 114, 080402 or also arXiv:1410.8784), we realize a simple system consisting of a pair of atoms in a two-site “minicrystal” and reproduce the physics of a widely used model of electrons in a solid. By combining many such “minicrystal” we aim for the deterministic preparation of larger systems and new insights into complex quantum many-body physics.
The publication was selected for a Viewpoint in Physics, which was written by Cindy Regal and Adam Kaufman from the University of Boulder, CO. It was also featured as a Brennpunkt in the Physik Journal of the DPG, written by Dieter Jaksch.

More information can be found in the press release (in English or German) from the University of Heidelberg.

PhD thesis finished

last modified on February 18 2015 17:07

Martin recently finished his PhD thesis. It describes the preparation of a 2D Fermi gas in the BEC-BCS crossover, the observation of pair condensation in this system and the measurement of its phase diagram.

The thesis is now available online: A Two-Dimensional Fermi Gas in the BEC-BCS Crossover

Imaging with matter-wave Fourier optics

last modified on February 09 2015 18:29

In our recent paper published in Physical Review A (also available at arXiv:1408.4680), we describe a simple technique to measure the momentum distribution of a strongly interacting quantum gas. We have used well known concepts from Fourier optics to investigate three operations on the gas: focusing, collimation and magnification. When we apply these techniques in our experiment, we see a prominent occupation of low momentum states that was not visible in the in-trap density distribution.

Master's thesis finished

last modified on February 09 2015 17:32

Sebastian finished his Master's thesis on the BKT-phase transition in a strongly interacting 2d Bose gas. We're very sad to see you go and wish you all the best, Sebastian!

EDV Abteilung