Entangling gate performance and fidelity limits with neutral atom F\"orster resonances

Abstract:Neutral-atom entangling gates are commonly analyzed with a single effective Rydberg-pair state, but near Förster resonances the pair manifold contains resonantly coupled interaction channels that change both the control landscape and the achievable fidelity. We develop a two-eigenstate model for this regime and show that when allowing for coupling to both pair states in the resonance, the gate fidelity is bounded by $\mathcal{F}\leq 1-(\pi/2)/(V\tau_R)$, for interaction strength $V$ and Rydberg lifetime $\tau_R$. We construct a gate protocol that saturates this bound in the large-Rabi-frequency limit, improving the existing fidelity limit by approximately $40\%$. We also evaluate common gate protocols near Förster resonances and find that retaining the exchange dynamics increases predicted fidelities by up to two orders of magnitude over earlier treatments.

Quantum Physics (quant-ph); Atomic Physics (physics.atom-ph)

arXiv:2605.19245 [quant-ph]

(or arXiv:2605.19245v3 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2605.19245 Focus to learn more arXiv-issued DOI via DataCite

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