Quantum Computing with Circular Rydberg Atoms

Abstract

Rydberg-atom arrays are a leading platform for quantum computing and simulation, combining strong interactions with highly coherent operations and flexible geometries. However, the achievable fidelities are limited by the finite lifetime of the Rydberg states, as well as by technical imperfections such as atomic motion. In this work, we propose a novel approach to Rydberg-atom arrays using long-lived circular Rydberg states in optical traps. Based on the extremely long lifetime of these states, exceeding seconds in cryogenic microwave cavities that suppress radiative transitions, and gate protocols that are robust to finite atomic temperature, we project that arrays of hundreds of circular Rydberg atoms with two-qubit gate errors around 10^{−5} can be realized using current technology. This approach combines several key elements, including a quantum-nondemolition detection technique for circular Rydberg states, local manipulation using the ponderomotive potential of focused optical beams, a gate protocol using multiple circular levels to encode qubits, and robust dynamical-decoupling sequences to suppress unwanted interactions and errors from atomic motion. This represents a significant improvement on the current state of the art in quantum computing and simulation with neutral atoms.