Many-body Chemical Reactions in a Quantum Degenerate Gas

Chemical reactions in the quantum degenerate regime are described by mixing of matterwave fields. Quantum coherence and bosonic enhancement are two unique features of many-body reactions involving bosonic reactants and products. Such collective reactions of chemicals, dubbed "super-chemistry", is an elusive goal in quantum chemistry research. Here we report the observation of coherent and collective reactive coupling between Bose condensed atoms and molecules near a Feshbach resonance. Starting from an atomic condensate, the reaction begins with a rapid formation of molecules, followed by oscillations of their populations in the equilibration process. Faster oscillations are observed in samples with higher densities, indicating bosonic enhancement. We present a quantum field model which describes the dynamics well and identifies three-body recombination as the dominant reaction process. Our findings exemplify the highly sought-after quantum many-body chemistry and offer a new paradigm for the control of quantum chemical reactions.