Long range detection of a single Rydberg qubit via hopping with Rydberg polariton*

Rydberg atom arrays have emerged as a powerful platform for quantum simulation and quantum computation. While recent efforts focused on scaling and gate fidelity improvement, further effort is needed to improve one of the slowest and most destructive stages of these systems - the readout. In our work we explore a new detection approach that utilizes collectively enhanced imaging in high optical density ensembles, based on Rydberg interactions in combination with electromagnetically induced transparency. Using this method we demonstrate lossless, high-speed readout of a single Rydberg-state qubit placed near a detector ensemble. We show that doing parallel readout is possible by multiplexing several ensembles and that detection works at surprisingly long distances. We provide a theoretical model that recovers our results and maps out the detector’s full operational range - blockade at short distances, classical hopping at very large distances and coherent flopping at intermediate distances - where due to coherent interaction of Rydberg qubit and detector polaritons, suppressed signals are observed.