Our lab is now making molecular Bose-Einstein condensates (mBEC)!

Congratulations to Dr. Yun Long and the lithium team as they are now evaporating ultracold lithium-6 atoms into molecular Bose-Einstein condensates. This unique cold-atom phase starts with our magneto-optical trap (MOT) after which we do gray molasses cooling on the lithium-D1 line. Then, the atoms are loaded into a high power laser beam (similar to so-called optical tweezers), of which the intensity is gradually reduced. As the trap becomes weaker, the hot atoms escape, leaving a lower temperature gas behind. This evaporative cooling process continues until the atoms stick together in molecular pairs similar to nitrogen or oxygen molecules in air (note however, that our molecules are not in the ground state, but are instead quite weakly bound). Finally, when the temperature is low enough, these molecular pairs for the Bose-Einstein condensate, seen above as a sharp increase in the density of atoms with near-zero momentum. The images show (approximately) the momentum distribution of the molecules. The above images contain about 200,000 molecules at various temperatures near 500 nanoKelvin. Using these condensates, we have an exciting array of experiments planned to test correspondence between these cold atoms and electrons in materials with unusual properties. Stay tuned!

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