Few-body Förster resonances in Rydberg atoms for quantum gate protocols

• Ivan Ashkarin (FOP, LTE)

Room: Salle Danjon Neutral atoms arranged in reconfigurable arrays of optical tweezers present a promising platform for scalable quantum computing. Despite notable progress, the realization of long-range multi-qubit gates remains a key challenge. Limited connectivity, due to the short-range nature of commonly used van der Waals interactions, constrains the complexity of quantum circuits feasible on current NISQ devices. A promising strategy to overcome this limitation involves Stark-induced Förster resonances. By applying an external electric field, the Förster energy defect between collective Rydberg states can be tuned, leading to a resonant enhancement of dipolar interactions in the array. This enables coherent gate operations between qubits separated by tens of micrometers, significantly extending spatial connectivity. Here, we present theoretical results on Stark-tuned Förster resonance transfers in ordered arrays of Rb and Cs atoms. In this study, we have designed several high-fidelity (up to 99.7%) protocols for three-qubit Toffoli and CCPHASE gates. We have also proposed techniques to improve robustness against experimental imperfections, including the use of spatially stable resonances and DC-inaccessible two-body transitions.