Quantum gas of deeply bound ground state molecules

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Chemistry
• Condensed Matter Physics

Background:

• Dissipating translational and internal energy is challenging for molecular cooling due to complex energy spectra.
• Creating ultracold quantum gases of molecules is crucial for fundamental research and quantum technologies.

Purpose of the Study:

• To develop a method for creating translationally ultracold, dense quantum gases of molecules.
• To demonstrate the coherent transfer of atoms into molecules with tight chemical bonds.
• To assess the feasibility of reaching a Bose-Einstein condensate of molecules in their rovibronic ground state.

Main Methods:

• Creation of a Bose-Einstein condensate of cesium atoms.
• Stimulation of an 80% efficient two-photon transfer from Feshbach molecules to tightly bound molecules.
• Coherent transformation of long-range electrostatic bonds into short-range chemical bonds.
• Ramsey-type spectroscopy to demonstrate transfer coherence and measure sample heating.

Main Results:

• Generation of a translationally ultracold, dense quantum gas of molecules in the electronic ground state.
• Demonstration of coherent two-photon transfer with high efficiency.
• Confirmation that the molecular sample remains cold during the transfer process.
• Evidence of the transformation from Feshbach molecules to molecules with chemical bonds.

Conclusions:

• Preparation of quantum gases of molecules in specific rovibrational states is achievable.
• The presented method is a significant step towards creating Bose-Einstein condensates of molecules in their rovibronic ground state.
• This work opens new avenues for ultracold molecule research and applications.