Quantum gas of deeply bound ground state molecules.
Molecular cooling techniques face the hurdle of dissipating translational as well as internal energy in the presence of a rich electronic, vibrational, and rotational energy spectrum. In our experiment, we create a translationally ultracold, dense quantum gas of molecules bound by more than 1000 wave numbers in the electronic ground state. Specifically, we stimulate with 80% efficiency, a two-photon transfer of molecules associated on a Feshbach resonance from a Bose-Einstein condensate of cesium atoms. In the process, the initial loose, long-range electrostatic bond of the Feshbach molecule is coherently transformed into a tight chemical bond. We demonstrate coherence of the transfer in a Ramsey-type experiment and show that the molecular sample is not heated during the transfer. Our results show that the preparation of a quantum gas of molecules in specific rovibrational states is possible and that the creation of a Bose-Einstein condensate of molecules in their rovibronic ground state is within reach.
Danzl
Johann G
JG
Institut für Experimental physik und Zentrum für Quantenphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria. johann.danzl@uibk.ac.at
Haller
Elmar
E
Gustavsson
Mattias
M
Mark
Manfred J
MJ
Hart
Russell
R
Bouloufa
Nadia
N
Dulieu
Olivier
O
Ritsch
Helmut
H
Nägerl
Hanns-Christoph
HC