Integrating Rydberg-state control of atom-atom interactions with cavity control of atom-light interactions enables the combination of local entangling operations with photon-mediated long-range coupling, measurement, and communication. Such integration is challenging because electric fields generated by charges on cavity optics and by cavity-stabilizing actuators may disturb Rydberg-state coherence. Here, we couple a Rydberg tweezer array to a high-cooperativity optical cavity, suppressing the electric fields produced by cavity length actuation so that the residual field variation of about
3 mV/cm rms does not limit Rydberg coherence. We demonstrate two capabilities that neither system provides alone. First, we use Purcell-enhanced fluorescence to read out atoms directly in the ground-Rydberg basis within
7.5 μs, well within the Rydberg-state lifetime, with ground- and Rydberg-state detection infidelities of
3% and
5%, respectively, and with low atom loss. Second, we use Rydberg-Rydberg interactions to control collective light-atom scattering into the cavity mode. Specifically, we drive blockaded Rabi oscillations between a state with two ground-state atoms, which scatter collectively with a superradiant or subradiant rate controlled by the atomic positions, and an entangled state with a single Rydberg excitation, which scatters like a single atom. These capabilities open routes toward networked Rydberg processors, mid-circuit measurements in analog quantum simulators, and many-body quantum optics with entangled emitters coupled collectively to light.
This Research Letter reports on the observation of superradiance decoherence caused by long-range dipole-dipole interactions between Rydberg atoms. A cold atom cloud is prepared in the mode volume of a weakly driven optical cavity and excited to a Rydberg state. The cavity transmission monitors the Rydberg dynamics in real time and detects superradiant enhancement of the transition rates between neighboring Rydberg states. The observed enhancement is reduced for increasing Rydberg atom density: a signature of atom pair interactions. The observations are explained within a model based on the idea of Rydberg blockade reducing the atom number participating in the Dicke state, responsible for superradiance.