April 08, 2026 -- A research team at the Max Planck Institute of Quantum Optics (MPQ) has realised quantum gates using fermionic atoms, achieving an accuracy of 99.75% and lifetimes exceeding ten seconds – a record. The platform relies on atoms that obey the same quantum-mechanical rules as electrons in materials, enabling the direct study of fermionic systems. By implementing digital quantum gates in an analogue quantum simulator platform, the work opens a new hybrid approach to materials research, quantum chemistry, and the study of complex quantum systems. The results were published today in Nature.

Fermions, such as electrons, protons, and even whole atoms, obey rules that shape the properties of many materials: One of the most important is that no two fermions can occupy the same quantum state at the same time. Their interactions are highly complex, but understanding them is essential to describing physical systems.

Even the most powerful classical supercomputers reach their limits when modelling fermionic interactions, as the number of possible quantum states grows rapidly with each additional particle. Conventional quantum computers do not solve this problem directly, either. They rely on qubits which follow different statistical rules than fermions. The distinctive exchange statistics of fermions must therefore first be translated into the language of qubits through complex transformations - an additional computational burden that significantly complicates simulations.

The MPQ team pursued a different approach, developing a “natural” quantum computer based on genuine fermionic particles: “Instead of calculating electrons in a complicated way, we recreate their behaviour directly,” explains Titus Franz, the study’s senior author. “This allows us already today to explore large quantum systems and, for example, gain a better understanding of superconductivity.”

An egg carton made of light

For their “natural” quantum computer, the researchers cool atoms to extremely low temperatures and arrange them in an optical lattice resembling a three-dimensional egg carton made of light. Within this structure, the atoms can be made to collide in a controlled manner. When they do, they exchange information and become entangled – remaining quantum-mechanically linked even after separating.

By precisely observing and controlling individual atoms, the researchers have now realised a key quantum gate: the spin-exchange gate. Quantum gates are the fundamental operations of a quantum computer. Of particular importance are those that entangle particles – coupling them quantum mechanically – and thereby enable complex quantum algorithms.

The starting point is a “double well”: two adjacent potential minima in the optical lattice, each occupied by a single atom. Initially, one well contains an atom with spin-up and the other an atom with spin-down. Spin denotes an intrinsic property of the atom, comparable to a tiny magnet.

When atoms swap places

To implement the quantum gate, the team lowered the barrier between the two wells, allowing the atoms to interact briefly. Although the atoms appear randomly distributed in the quantum gas microscope, they remain perfectly anti-correlated: if one atom is found in one well, the other is automatically located in the opposite one. In this way, entangled quantum states are created, forming the basis for quantum computation.

Repeated sequences showed an accuracy of 99.75%, comparable to the best quantum gates in neutral-atom systems. The generated quantum states remained entangled for over ten seconds – exceptionally long for a quantum system, and many orders of magnitude longer than the gate duration itself.

“With the quantum gas microscope, we can track the dynamics of every single atom,” says first author Petar Bojovic. “This gives us a much deeper understanding of the overall system, allowing us to identify errors in a targeted way, and optimise the processes. In future, we aim to extend these methods to control individual atoms as well.”

New perspectives for quantum logic

The experiments show that controlled collisions between atoms enable precise quantum operations with high fidelity, establishing a new platform for quantum computing. “What is particularly exciting is that we can now use the same platform previously employed for analogue quantum simulation for digital operations as well,” comments Titus Franz. “This allows us to combine the best of both worlds: the simulation of large quantum systems over long timescales, while performing precise quantum gates for new observables. One goal is to study high-temperature superconductivity directly.”

In the long term, the team plans to scale up the systems further and introduce local control over individual atoms. The aim is to realise even larger and more precise quantum circuits and to open up new avenues for programmable fermionic quantum processors. This could pave the way for future applications in quantum chemistry and the development of novel materials.