Neutral-atom quantum computation using multi-qubit geometric gates via adiabatic passage

Abstract: Adiabatic geometric phase gates offer enhanced robustness against fluctuations compared to con- ventional Rydberg blockade-based phase gates that rely on dynamical phase accumulation. We theoretically demonstrate two- and multi-qubit phase gates in a neutral atom architecture, relying on a double stimulated Raman adiabatic passage (double-STIRAP) pulse sequence that imprints a controllable geometric phase on the qubit systems. The system is designed in such a way that every atom is individually addressable, and moreover, no extra laser is required to be applied on the target atom while scaling up the system from two- to multi-qubit quantum gates. The gate fidelity has been numerically analyzed by changing the gate operation time, and we find that 98% to 99% fidelity can be achieved for gate time $\simeq$ 0.6 $\mu$s. We perform a systematic error analysis, which re- veals that our proposed gates can exhibit strong resilience against fluctuations in Rabi frequencies, finite blockade strength, and atomic position variations. These results establish our approach as a physically feasible and scalable pathway toward fault-tolerant quantum computation with neutral atoms. We simulate Grover's search algorithm for two-, three-, and four-qubit systems with high success probability and thereby demonstrate the utility and scalability of our proposed gates for quantum computation.