University of Chicago researchers are pursuing a new quantum computer design that uses the unique properties of helium-3, an isotope distinct from the helium used in MRI machines and balloons. The team, led by Assoc. Jacob Covey, reports that using helium, the lightest atom that can be laser-cooled and controlled, could achieve quantum tunneling rates three times faster than those possible with lithium. “Helium is even lighter than lithium, so that provides quantum tunneling rates about three times faster, at least,” said co-first author Zheyuan Li, a PhD student in Covey’s lab.
Peers in the scientific community have praised the innovation. “By using the lightest trappable atom, this work turns low mass into a real advantage—faster tunneling, faster transport, and controllable motional qubits,” said Princeton University Physics Prof. Waseem Bakr, who was not involved in the research. The next step involves collaborating with UChicago Physics Asst. Zoe Yan to trap and control individual helium-3 atoms within the next one to two years.
Laser-Trapped Helium Enables Faster Quantum Tunneling
Helium’s well-resolved energy structure simplifies laser cooling compared to lithium atoms, an important step in preparing qubits for computation. This enhanced ease of cooling directly addresses a significant challenge in quantum computer design, allowing for more precise control over atomic states and reducing decoherence. The team’s approach uses helium-3, a specific isotope chosen for its distinct quantum properties, differentiating it from the more common helium-4 used in conventional applications.
This speed increase is not merely incremental; it directly impacts processing capabilities, potentially enabling more complex calculations within a given timeframe. While two grams of helium contains a 3 followed by 23 zeroes atoms, the computer requires only tens for operation, ensuring a sustainable resource. According to the published work in PRX Quantum, this design offers a pathway toward more natively implementing fermionic quantum computing, avoiding the complexities of simulating fermionic structure with bosonic atoms like helium-4.
By using the lightest trappable atom, this work turns low mass into a real advantage – faster tunneling, faster transport, and controllable motional qubits. It’s a compelling blueprint for the next generation of fermionic quantum simulators.
Waseem Bakr, Physics Prof. at Princeton University
Helium-3 Isotopes Support Fermionic Quantum Computing
Using helium-3’s intrinsic quantum properties, the design distinguishes itself from earlier fermionic approaches. Unlike helium-4, helium-3 eliminates the need to simulate fermionic behavior; it embodies it natively. “That would help us to implement fermionic quantum computing much more natively with this platform, rather than trying to use bosonic atoms like helium-4 and then trying to simulate fermionic structure,” explained author Zheyuan Li. This native implementation promises to reduce errors inherent in approximating fermionic systems with bosonic ones, a significant hurdle in quantum computation.
While hydrogen-2, another fermionic isotope, exists, researchers deemed helium-3 not even much lighter than hydrogen-2. They plan to initially test the system with helium-4, a bosonic isotope, before transitioning to the fermionic helium-3, establishing a clear progression for experimental validation. The foundation for this advancement is now in place.
That would help us to implement fermionic quantum computing much more natively with this platform, rather than trying to use bosonic atoms like helium-4 and then trying to simulate fermionic structure.
Zheyuan Li, PhD student in Covey’s lab
Metastable Helium States Enhance Atom Control
Helium’s ability to linger in a metastable state for up to two hours distinguishes it from other elements considered for quantum computing, offering a prolonged window for manipulation. Unlike lithium, and other single-electron atoms requiring an immediate jump to an excited state, helium can be temporarily held at an intermediate energy level, simplifying the process of laser-induced excitation. This metastable state isn’t merely a convenience; it fundamentally alters the energy requirements for trapping the atom.
While hydrogen, despite being the lightest element, proves untrappable due to the high energy needed for excitation, helium’s two electrons allow for a stepped approach, reducing the energy demand. The team specifically intends to utilize helium-3, an isotope differing from the common helium-4 found in balloons by a single neutron, due to its unique quantum properties.
The foundation is there, and the progress is advancing now to the point where we would hope to have these atoms in tweezers for the first time probably within the next year or two.
Jacob Covey, Assoc
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