High-fidelity entanglement of polar molecules by dynamic geometric control

Optical tweezer arrays of polar molecules are a promising platform for quantum science, providing long-lived rotational qubit states with programmable long-range dipolar interactions. However, the achievable dipolar coherence and thus entanglement depth, has been significantly limited by thermal motion and residual positional noise of molecules in tightly focused traps. In this work, we experimentally show three-dimensional geometric control of the relative configuration of the interacting molecular pairs and identify multiple geometric conditions that minimize the sensitivity of dipolar interactions to motional dephasing. Using a combination of "magic" geometries and partial Raman sideband cooling, we observe substantially enhanced coherence of dipolar spin dynamics, even when molecules are not in the motional ground state. These results establish geometric engineering as a practical method towards high-fidelity many-body dynamics in molecular quantum processors and simulators