Coherent synthesis of molecules in atomic Bose-Einstein condensates Zhendong Zhang, Kai-Xuan Yao, Shu Nagata, Cheng Chin

Chemical reactions in the quantum degenerate regime can be drastically different from that in a normal thermal gas. Quantum statistics and collective behavior can dominate the reaction kinetics once the reactants are prepared close to their many-body ground state. Here we report coherent molecule formation processes in atomic Bose-Einstein condensates (BECs) near a g-wave Feshbach resonance. The molecule formation rates sharply transition from the values determined by thermal collisions between atoms to those in the degeneracy regime where the wave nature of atoms dominates, as we reduce temperature to below the critical temperature. Starting from an almost pure atomic BEC, the number of produced molecules shows coherent oscillatory evolution with the oscillation frequency determined by both the molecular binding energy and the atomic density. We further enhance the amplitude of the molecule number oscillation by periodically modulating the molecular binding energy. Our observation demonstrates collective chemical reactions in a strongly interacting atomic BEC.