Trimers,Tetramers and molecular BEC

ongoing

"A major challenge in physics is to prepare and control increasingly complex physical systems at ultracold temperatures down to the quantum level. Precise control allows analyzing the universal features of the system and, at the same time, enables tackling more complex systems. This development has led from atomic control to few- and many-body quantum systems. Similarly, atomic control has enabled the preparation and study of diatomic molecules - a development the PI of this proposal has significantly contributed to. Our aim is to drive the next milestone on the path to increasingly complex quantum systems in the ultracold. We will make use of collisional processes and photoassociation in ""chemically stable"" atom-molecule and molecular quantum gases to progress beyond diatomic molecules to weakly bound trimers and tetramers. We will feedback the developed understanding of these small polyatomic molecules to controlling atom-molecule and molecule-molecule collisions - currently a hot topic in itself - and possibly enable the realization of the first BEC of diatomic ground-state molecules. The experiments will start from atom-molecule quantum gas mixtures of 39K and 23Na39K and pure molecular quantum gases of 23Na39K as available in the PI’s laboratory and enable studies of weakly bound NaK2 and Na2K2. We will detect trimers and tetramers and information about their quantum state by ion spectrometry – a method from physical chemistry. If successful, the proposal will extend significantly beyond the state of the art. It will extend the world of ultracold gases to small, weakly bound polyatomic molecules, provide insight into the building of simple molecular systems, and how few-body systems change with increasing number of atoms. It might enable precision control of diatomic molecule collisions, the longed-for BEC of polar molecules, and might unlock the full potential of polar molecules for dipolar quantum many-body physics."