Collectively Enhanced Molecule Formation in a Cavity Using Dissipative Effects

Ultracold molecules provide a controlled environment to study quantum many-body effects in physics and chemistry but creating samples with high phase-space densities has proven challenging. We propose a mechanism to realize high-yield formation of ultracold ground state molecules. We consider an ensemble of atom pairs trapped inside an optical cavity. The atom pairs are continuously excited by a laser, followed by a collective decay into the molecular ground state induced by a coupling to the lossy cavity mode. We adiabatically eliminate the excited states and the cavity mode and derive a master equation which describes purely dissipative population transfer of initial atom pairs to the molecular ground state. The ground state yield can be improved by simply increasing the number of initial atom pairs, however at the cost of a slowdown of the transfer. We identify polariton formation as the source of this slowdown, and discuss how to mitigate it by tuning in resonance with the polaritons. We study realistic experimental setups, where our method can overcome efficiencies of state-of-the-art association schemes. This opens up collective light matter interactions as a tool for quantum state engineering, enhanced molecule formation, collective dynamics, and cavity mediated chemistry.