High-fidelity multiqubit Rydberg gates via two-photon adiabatic rapid passage

Neutral atom arrays are a promising platform for quantum information processing. One of the crucial advantages of this architecture is the ability to implement native multiqubit operations by exploiting the strong interactions between highly excited Rydberg states. In this work, we present a robust protocol for realizing high-fidelity multiqubit controlled phase gates (C^kZ) on neutral atom qubits. Our scheme is based on extending adiabatic rapid passage to two-photon excitation via a short-lived intermediate excited state, as is typical in alkali-atom Rydberg experiments. We evaluate and optimize gate performance for Cs atoms accounting for the full impact of spontaneous decay and differential AC Stark shifts from the complete manifold of hyperfine excited states, concluding that a CCZ gate with fidelity F>0.995 for three qubits and CCCZ with F>0.99 for four qubits is attainable in ~1.8 μs for currently available laser frequencies and powers, with future technologies allowing access to higher fidelities.