2024/11/10 by Н. Н. Безуглов, I. I. Beterov, Bezuglov, N. N. +19
Physics and Astronomy · #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.2411.06607
openalex publication_date 2024/11/10 · openalex created_date 2024/11/15 · openalex updated_date 2026/07/28
Precise individual addressing of single atoms in quantum registers formed by optical trap arrays is essential to achieve high-fidelity quantum gates in neutral-atom quantum computers and simulators. Two-qubit quantum gates are typically realized using coherent two-photon laser excitation of atoms to strongly interacting Rydberg states. However, two-photon excitation encounters challenges in individual addressing with tightly focused laser beams due to atom position uncertainty and the spatial inhomogeneity in both Rabi frequencies and light shifts. In this work, we theoretically demonstrate that the fidelity of individual addressing can be improved by employing coherent three-photon laser excitation of Rydberg states. For a specific example of 5s1/2 \xrightarrowΩ1 5p3/2 \xrightarrowΩ2 6s1/2 \xrightarrowΩ3 np excitation in 87Rb atoms, we find that upon strong laser coupling in the second step (Rabi frequency Ω2) and moderate coupling in the first and third steps (Rabi frequencies Ω1 and Ω3), the three-photon Rabi frequency is given by Ω = Ω1Ω3/Ω2. If the spatial distributions of (Ω1Ω3) and Ω2 are arranged to be identical, Ω becomes independent of atom position, even within very tightly focused laser beams. This approach dramatically improves individual addressing of Rydberg excitation for neighboring atoms in trap arrays compared to conventional two-photon excitation schemes. Our findings are crucial for large-scale quantum registers of neutral atoms, where distances between adjacent atoms should be minimized to ensure stronger Rydberg interactions and compact arrangement of atom arrays.