Delta-kick collimation of heteronuclear Feshbach molecules

We present a theoretical study of delta-kick collimation (DKC) applied to heteronuclear Feshbach molecules, focusing on both condensed and thermal ensembles across various interaction and temperature regimes. We demonstrate that DKC enables significant reductions in molecular cloud expansion energies and beam divergence, achieving expansion energies in the picokelvin range, comparable to state-of-the-art results obtained experimentally with atoms. Furthermore, we show that vibrational and translational motions remain strongly decoupled throughout the process, and that the vibrational energy remains well below the molecular binding energy, thereby ensuring molecular stability during the delta kick. This work paves the way for advanced experimental sequences involving degenerate ground-state molecules, light-pulse molecular interferometry, and applications of dual-species precision measurements, such as testing the universality of free fall.