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arXiv · 2602.18567

Four- and six-photon stimulated Raman transitions for coherent qubit and qudit operations

Gabriel J. Gregory·Evan R. Ritchie·Alex Quinn·Sean Brudney·David J. Wineland·David T. C. Allcock·Jameson O'Reilly
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Abstract

Quantum computers are typically composed of an array of two-level systems, or qubits, encoded in some information carrier, such as an electron, photon, or quantized circuit. The size of this array is restricted by finite access to resources like laser power, cooling capacity, and control lines for trapping and manipulation. Under these constraints, the system's processing power can be increased by using more energy levels per information carrier, but common techniques for qubit control provide only limited connectivity between these additional states. We experimentally demonstrate transitions between electronic angular momentum states with a difference in magnetic quantum numbers $\Delta \mathrm{m_J} = $ 3, 4, and 5 via resonant four- and six-photon stimulated Raman transitions in a single trapped atom. Derivation of the corresponding Rabi frequencies, which are verified experimentally, follows the standard treatment of two-photon transitions including the adiabatic elimination of intermediate states. Finally, we discuss pathways to increase the observed multi-photon transition fidelities to $>99.99\%$, providing a tool for efficient, high-fidelity control of qudits and single-atom logical qubits.

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Gabriel J. Gregory, Evan R. Ritchie, Alex Quinn, Sean Brudney, David J. Wineland, David T. C. Allcock, Jameson O'Reilly. 2026-02-20. Four- and six-photon stimulated Raman transitions for coherent qubit and qudit operations. https://arxiv.org/abs/2602.18567

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