Frankfurt 2006 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 38: Quantengase IV

Q 38.7: Vortrag

Mittwoch, 15. März 2006, 12:10–12:25, HVI

Feshbach molecules from an atomic Mott insulator — •Niels Syassen, Thomas Volz, Dominik Bauer, Eberhard Hansis, Stephan Dürr, and Gerhard Rempe — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching, Germany

Feshbach molecules from bosonic atomic species have proven to be very unstable with respect to inelastic collisions [1]. As a result, the typical lifetime observed for a cloud of ultracold ⁸⁷Rb₂ molecules stored in an optical dipole trap is limited to a few milliseconds.
Here, we report on the observation of long-lived Feshbach molecules in an optical lattice. A BEC of ⁸⁷Rb atoms is loaded into the lowest Bloch band of a 3D optical lattice operated at a wavelength of 830 nm. By ramping up the lattice depth, the atomic gas enters the Mott insulator regime. A magnetic-field ramp through the Feshbach resonance at 1007 G creates molecules [2]. Lattice sites initially occupied with more than 2 atoms experience fast inelastic collisional losses. The observed lifetime of the remaining molecules is ∼ 100 ms, which is much longer than for a pure molecular sample in an optical dipole trap. Similar results have recently been reported in Ref. [3]. The increased lifetime is an important step on the route to a BEC of molecules in the vibrational ground state [4].

[1] T. Mukaiyama et al., Phys. Rev. Lett. 92, 180402 (2004)

[2] S. Dürr et al., Phys. Rev. Lett. 92, 020406 (2004)

[3] G. Thalhammer et al., cond-mat/0510755

[4] D. Jaksch et al., Phys. Rev. Lett. 89, 040402 (2002)