High-fidelity two-qubit quantum gates with neutral atoms

Neutral atom arrays have recently emerged as a leading quantum computing platform, enabling coherent control of hundreds of atoms in programmable two-dimensional arrays [1], as well as digital quantum computation in a dynamically reconfigurable architecture [2]. The platform’s scalability and all-to-all connectivity make it a unique approach for realizing novel quantum circuits and quantum error correction protocols. A key requirement for such applications is high-fidelity two-qubit operations. In particular, fidelities exceeding 99% are important for surpassing most current error correction thresholds. We report experimental realization of a new family of two-qubit quantum entangling gates, demonstrating fidelities of 99.5% while operating on tens of atoms in parallel. Our approach combines robust single-pulse Rydberg gate schemes inspired by Jandura and Pupillo [3], dark-state physics to suppress intermediate state scattering, and improvements to Rydberg excitation and atom cooling. We benchmark this two-qubit gate fidelity by multiple repeated gate applications, characterize the physical error sources, and identify a path toward higher fidelities. This advance, along with the ability to generate nonlocal connectivity through coherent atom transport and natural scalability to 1000s of atoms, lays the groundwork for large-scale control of error-corrected logical qubits. Finally, we provide an overview of ongoing experimental upgrades, including local control and mid-circuit feedback capabilities, and discuss the scientific frontiers opened by this work.

[1] Ebadi et al., Nature 595, 227-232 (2021).

[2] Bluvstein et al., Nature 604, 451-456 (2022).

[3] Jandura and Pupillo, Quantum 6, 712 (2022).