Most quantum computing platforms are built around one kind of qubit. Superconducting circuits work one way, trapped ions another, and each platform spends years optimizing its single approach. A team at JILA (University of Colorado and NIST) has taken a different path: build a system where the same atom can serve as three different kinds of qubit, and move quantum information between them at will.
The result, published June 12 in Nature Physics, demonstrates that ytterbium-171 atoms in optical tweezer arrays can host nuclear spin qubits, Rydberg qubits, and optical clock qubits simultaneously, and that entanglement can be transferred coherently between all three types without destroying the quantum correlations.
Why three qubit types?
The ytterbium atom’s energy level structure is unusually rich. Each of its three qubit types serves a different purpose:
- Nuclear spin qubits (the ground and metastable electronic states) are robust and long-lived, making them suitable for storing quantum information and performing computations.
- Rydberg qubits use highly excited electronic states where electrons orbit far from the nucleus. These states are enormous, thousands of times larger than the ground state, which lets them interact strongly with neighboring atoms through the Rydberg blockade mechanism. This is how the team creates entangling gates.
- Optical clock qubits use the ultra-narrow clock transition, a transition so precise it forms the basis of atomic clocks. These qubits are designed for quantum sensing and metrology, measuring time, gravity, and electromagnetic fields with exquisite precision.
The ability to map quantum states between these three types means the same physical hardware can serve as a quantum computer, a quantum simulator, and a quantum sensor.
The numbers
The team, led by Adam Kaufman at JILA, arranged ytterbium atoms in a two-dimensional ladder configuration using optical tweezers. They used Rydberg-mediated two-qubit CZ gates to create entangled states, then transferred those states to other qubit types.
The measured error-detected two-qubit gate fidelity reached 99.78 percent, approaching the thresholds needed for fault-tolerant quantum error correction. They also created Greenberger-Horne-Zeilinger (GHZ) states, a form of multipartite entanglement, on up to 20 atoms in a two-dimensional arrangement.
A key advance was erasure conversion: the team used the clock qubit to detect when atoms were lost during operations, converting a major source of errors into detectable erasure errors. Erasure errors are much easier to correct than random computational errors, making this a critical step toward fault tolerance. The Rydberg decay detection efficiency exceeded 90 percent.
What this means
Neutral atom quantum computing has advanced rapidly in the past few years. Companies like Atom Computing and QuEra have demonstrated large arrays of neutral atoms with impressive coherence times. What the JILA result adds is versatility: instead of optimizing a single qubit type and struggling to make it do everything well, the ytterbium platform lets different qubit types handle different tasks while sharing the same quantum state.
This is particularly relevant for quantum networks, where you might need to compute with one qubit type, store the result in another, and interface with light via a third. Having all three in the same atom eliminates the need to transfer quantum information between physically separate systems, one of the hardest problems in quantum engineering.
The GHZ states on 20 atoms also demonstrate scalable multipartite entanglement in a programmable architecture, which is relevant for quantum error correction codes that require many entangled qubits working together.
The caveats
The 99.78 percent fidelity is the error-detected value, the fidelity after post-selecting on successful erasure detection. The raw fidelity before this correction is lower. Scaling from a moderate-size 2D ladder array to the larger, fully 2D arrays needed for practical quantum computing remains future work. And the mapping between qubit types adds operational overhead that must be factored into overall error budgets.
Nevertheless, the work establishes ytterbium-171 as a uniquely versatile platform, one where quantum computing, simulation, and sensing are not separate machines but different programs running on the same atoms.
Source: Senoo, A., Baumgartner, A., Lis, J.W., Vaidya, G.M., Zeng, Z., Giudici, G., Pichler, H., & Kaufman, A.M. (2026). High-fidelity entanglement and coherent multi-qubit mapping in an atom array. Nature Physics. DOI: 10.1038/s41567-026-03258-8. arXiv: 2506.13632