DFG-Research Unit 801 | DFG-Forschergruppe 801


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Strong Correlations in Multiflavor Ultracold Quantum Gases

Strong correlations have been studied for many decades, particularly in condensed matter and nuclear physics. They play a crucial role in understanding complex phenomena like superconductivity, metal-insulator transitions or the excitation spectra of nuclei. Building on the achievement of Bose-Einstein-Condensation (BEC) and degenerate Fermi gases in ultracold atomic vapors, strong correlation phenomena have recently been shown to appear even in such dilute gases. This has opened a new chapter in atomic and molecular physics, where interactions rather than single particle physics are at center stage.

Two of the major tools which allow to enter the regime of strong correlations in cold gases are optical lattices and Feshbach resonances. Together they allow for an almost perfect tunability of the effective interaction strength, providing an ideal realization of most of the basic models in many body physics. Prominent examples are Bosons on an optical lattice or attractive Fermions near a Feshbach resonance. They exhibit a superfluid-insulator transition or an intermediate regime between a BCS- and a BEC-type superfluid, phenomena which have never before been accessible in condensed matter physics. Here we propose to study strong correlations in cold gases with internal (spinor) degrees of freedom, in mixtures of Bose and Fermi gases and in degenerate gases subject to static disorder potentials. These systems have hardly been explored so far and are expected to display a number of complex phenomena, which are among the most challenging and still poorly understood problems in many body physics.

The experimental groups in Hamburg, Mainz and Munich will realize and investigate degenerate gases, in particular spinor gases and Bose-Fermi and Fermi-Fermi mixtures, both with and without optical lattices. Using two component systems allows realizing static short-range potentials for one of the components. In a coordinated effort, the theoretical description will be provided by the theory groups in Aachen, Frankfurt and Munich, using both analytical and numerical techniques. The close collaboration between theory and experiment offers a unique possibility to explore fundamental issues in many body physics, like the competition between Anderson- and Mott-insulating phases in perfectly well defined and tunable systems.


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Quantum Optics Chair/
Fakultät für Physik

Prof. Immanuel Bloch

Schellingstr. 4
80799 Munich, Germany

Phone: +49 (0)89 2180 - 6130
Fax: +49 (0)89 2180 - 63851