Probing Dipolar Interactions between Rydberg Atoms and Ultracold Polar Molecules

Controlled interactions between quantum systems enable energy exchange and entanglement, underpinning many demonstrations in quantum simulation and information processing. While most work has focused on perfecting individual platforms, combining complementary systems could improve performance and mitigate platform-specific limitations. Here we focus on a hybrid system of ultracold molecules (⁴⁰K⁸⁷Rb ) and  Rydberg atoms (⁸⁷Rb), and probe interspecies dipolar interactions between them in an optically trapped ensemble. Using state-selective ionization detection of KRb molecules, we observe resonant energy transfer at 2.227 GHz from Rydberg atoms to molecules. We measure a broadening of the Rb Rydberg excitation spectrum up to 3.5 MHz, in agreement with a Monte Carlo simulation of a Rydberg atom and neighboring molecules evolving under a dipole–dipole interacting Hamiltonian. The demonstrated interspecies dipolar interaction is a key ingredient for this hybrid system and may open vastly different new research directions. I will also describe our efforts to extend this hybrid platform to a spatially regular array of NaCs molecules and Cs Rydberg atoms in optical tweezers.