Fast Preparation and Detection of a Rydberg Qubit Using Atomic Ensembles*

Arrays of neutral atoms have recently emerged as a competitive platform for quantum simulation and computation with many properties favorable for scaling. Rydberg states of atoms are often used because the strong Rydberg-Rydberg interactions can facilitate two-qubit gate operations and simulate many-body systems. However, for most schemes, readout of a Rydberg qubit is a destructive process that precludes its reuse and the application of many error-correcting codes. To address this challenge, we demonstrate a nondestructive implementation of preparation, manipulation, and readout of a single Rydberg qubit embedded in an atomic ensemble with high fidelity. By harnessing the collective optical response of the atomic ensemble, we detect the state of a qubit ~1000x faster than single-atom fluorescence imaging. This method determines the state of the Rydberg qubit without affecting the other atoms in the ensemble to first order, which can then be reused for further operations. With this developed technique, we are making progress towards realizing a quantum computer based on arrays of atomic ensembles, which can significantly improve the computation speed.