Abstract: An all-to-all coupled, high-fidelity, error-correctable quantum computer can scale to hundreds of qubits within a single cavity of moderate cooperativity with existing neutral atom technology. This quantum processor can enact teleported gates among any pair of qubits using a local Rydberg interaction between each qubit and a separate network of atoms that distribute entanglement via a cavity mode. Small atomic ensembles at network nodes allow for ultrafast, nondestructive readout with high fidelity by substantially shifting the resonance of even a poor-quality cavity. Fast readout enables near-deterministic entanglement distribution among network atoms despite cavity losses as well as syndrome measurements of qubit atoms for error correction.

Abstract: A quantum computer uses interactions between atomic ensembles mediated by an optical cavity mode to perform quantum computations and simulations. Using the cavity mode as a bus enables all-to-all coupling and execution of non-local gates between any pair of qubits. Encoding logical qubits as collective excitations in ensembles of atoms enhances the coupling to the cavity mode and reduces the experimental difficulty of initial trap loading. By using dark-state transfers via the cavity mode to enact gates between pairs of qubits, the gates become insensitive to the number of atoms within each collective excitation, making it possible to prepare an array of qubits through Poissonian loading without feedback.