Neutral Atom Qudits Achieve Full Control of Zeeman-Manifold Quintets
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Controlling and manipulating quantum information requires precise control over individual quantum bits, or qubits, and increasingly, higher-dimensional quantum systems known as qudits. Benedikt Heizenreder, Bas Gerritsen, and Katya Fouka, working with colleagues at the University of Amsterdam, now demonstrate a method for engineering these qudits using neutral atoms and carefully tuned light.
The team achieves this by combining magnetic and optical forces to control transitions between atomic energy levels, creating a five-level, or quintet, qudit system. This approach allows for full control over the qudit, including precise preparation of states, manipulation with radio-frequency fields, and rapid readout, with simulations predicting exceptionally high fidelities and fast operation speeds, establishing a promising pathway towards scalable quantum technologies based on multi-level quantum systems.
Strontium Rydberg Atoms in Optical Tweezers This body of work details research into neutral strontium atoms trapped and manipulated using optical tweezers, with a particular focus on Rydberg atoms and their potential for quantum technologies.
The team investigates precise control over individual atoms, leveraging their interactions for applications in quantum simulation and information processing. Research encompasses techniques for trapping, cooling, and controlling strontium atoms, alongside exploration of Rydberg states, which exhibit exaggerated properties useful for quantum systems. The group also develops advanced imaging techniques to observe and characterize these atomic systems with high resolution. Investigations extend to precision measurement and the development of atomic clocks, utilizing isotope shifts and carefully tuned laser wavelengths. The research explores many-body quantum phenomena, examining correlated states and collective behavior within these controlled atomic systems.
This research establishes a strong foundation for advancements in quantum computing and simulation, utilizing strontium atoms as a versatile platform for exploring fundamental quantum phenomena. Five-Level Qudits via Zeeman and Light Shifts Researchers have developed a technique to create and precisely control qudits—quantum information units with more than two levels—by exploiting transitions between Zeeman sublevels in individual atoms. Their work demonstrates the realization of a five-level qudit (quintet) encoded in the long-lived ( ^3P_2 ) state of neutral strontium-88 atoms trapped in far-detuned, σ⁻-polarized optical tweezers. By combining a strong external magnetic field, which produces a linear Zeeman shift, with a state-dependent light shift from the tweezers, the team lifted the degeneracy between adjacent Zeeman sublevels and tuned the resulting energy splittings into the radio-frequency regime. The researchers established full control over the quintet manifold, starting with initialization into a chosen basis state using a multi-photon transfer process. They then achieved coherent, state- and site-selective single-qudit rotations driven by RF fields, enabling precise manipulation of each atom’s quantum state. A fast, destructive optical readout scheme was also implemented to efficiently measure the final qudit state. Numerical simulations based on realistic experimental parameters predict state-preparation fidelities of up to 0.99 within about 1 microsecond, along with single-qudit gate fidelities near 0.99 using π-pulses lasting roughly 2.5 microseconds. Together, the high-fidelity control, rapid readout, and exceptionally long lifetime of the ( ^3P_2 ) state—exceeding tens of seconds—position strontium-based Zeeman qudits as a promising and scalable platform for future qudit-enabled quantum technologies. High-Fidelity Control of Strontium Qudits Achieved Scientists have achieved a breakthrough in qudit control by engineering a quintet encoded in the Zeeman sublevels of neutral strontium atoms confined in optical tweezers. This work demonstrates a general framework for high-fidelity control of these qudits, leveraging radio-frequency (RF) manipulation within a carefully engineered energy landscape.
The team combined a large linear Zeeman shift with a state-dependent light shift to lift the degeneracy between adjacent Zeeman sublevels, tuning their energy splittings into the RF domain and enabling precise control. Experiments, conducted through detailed numerical simulations using realistic parameters, predict state-preparation fidelities reaching 0. 99 within 1 microsecond, and single-qudit gate fidelities of 0. 99 with corresponding π-pulse durations of approximately 2. 5 microseconds. Furthermore, the simulations demonstrate fast destructive imaging with durations below 10 microseconds, enabling rapid readout of the qudit states. The research establishes a method for initializing the quintet into a specific basis state via multi-photon transfer, and for driving coherent, state- and site-selective single-qudit rotations using RF fields. The system benefits from the long lifetime of the 3P2 state in strontium, offering near-perfect isolation from imaging and cooling transitions while remaining compatible with established RF spin-control techniques. These results highlight the 3P2 manifold in strontium as a promising platform for scalable qudit-based quantum technologies, combining long coherence times with fast state preparation, precise rotation control, and rapid high-fidelity imaging. This achievement paves the way for advancements in quantum computing and simulation by offering a practical and scalable route to implement qudit-based technologies. High-Fidelity Control of Strontium Qudits This research demonstrates a general method for creating and controlling qudits, quantum systems with more than two levels, by manipulating transitions between Zeeman sublevels of atomic states.
The team successfully engineered a five-dimensional qudit, termed a ‘quintet’, within strontium atoms held in optical tweezers, achieving high-fidelity control over its quantum states. Simulations predict state preparation fidelities exceeding 97%, single-qudit gate fidelities of 98%, and rapid state readout within 100 microseconds, establishing a promising platform for scalable qudit-based technologies. The work incorporates realistic experimental imperfections, such as fluctuations in tweezer power and atomic motion, to model a feasible system. Researchers achieved precise control over the quintet, demonstrating the ability to transfer atoms to and from the ground state with high fidelity using multi-photon transfers and to perform numerous rotations while maintaining high fidelity. Future research will focus on further enhancing fidelities and improving the system’s robustness against environmental disturbances.
The team intends to explore advanced techniques like dynamical decoupling sequences and Hamiltonian-engineered decoupling to suppress dephasing and errors. Additionally, they plan to investigate methods for creating global superpositions across all five states and implementing two-qudit gates, paving the way for more complex quantum computations. 👉 More information 🗞 Engineering Zeeman-manifold quintets using state-dependent light shifts in neutral atoms 🧠 ArXiv: https://arxiv.org/abs/2512.14611 Tags: