While silicon and superconducting qubits often dominate the headlines, a different contender is quietly making a serious bid for quantum advantage: neutral atoms.
In late 2025, researchers from Lomonosov Moscow State University and Rosatom announced the successful testing of a 72-qubit quantum prototype powered by neutral rubidium atoms.
This achievement is not just about qubit count. It represents a fundamental architectural rethink of how quantum processors should be organized at scale.
The Core Technology: Rubidium Atoms in Optical Tweezers
In this system, each qubit is a single rubidium-87 atom.
Unlike ions, which carry electric charge and naturally repel one another, neutral atoms can be positioned densely without destabilizing the system. Researchers use optical tweezers—highly focused laser beams—to trap and arrange individual atoms inside a vacuum chamber.
To perform computations, lasers briefly excite the atoms into a Rydberg state, where their outer electrons extend far from the nucleus. In this state, atoms become extremely sensitive to nearby atoms, enabling the entangling interactions required for quantum logic gates.
This combination of isolation and controllable interaction is what makes neutral atoms such an attractive platform.
Solving the Noise Problem: The Three-Zone Architecture
The true innovation in the MSU–Rosatom prototype lies in the organization of the atoms.
Most quantum processors place all qubits in a single physical region. When lasers are applied to operate on one qubit, stray light can unintentionally disturb nearby qubits. This unwanted interference, known as crosstalk, is one of the most persistent sources of error in quantum hardware.
The Russian team addressed this by dividing the processor into three physically distinct zones, each with a dedicated role:
| Zone | Purpose | Function |
|---|---|---|
| Computing Zone | Active Processing | Atoms are brought here for laser-driven logic gates and entanglement |
| Storage Zone | Quantum Memory | Idle qubits are isolated and protected from operational noise |
| Readout Zone | Measurement | Final qubit states are measured without disturbing the rest of the system |
Atoms are physically shuttled between zones using movable laser traps, ensuring that high-power lasers used for computation never interfere with qubits waiting in storage.
This separation of function mirrors how classical computers isolate memory, processing, and input/output, and it represents a major step toward practical quantum architectures.
Why 72 Qubits Matter
Crossing the 70-qubit threshold is both a technical and psychological milestone.
At this scale, quantum systems begin to approach the limits of classical simulation. This is the regime in which quantum advantage becomes experimentally meaningful rather than merely theoretical.
Key performance indicators from the prototype include:
- Two-qubit gate fidelity: ~94%
While fault-tolerant quantum computing typically targets 99% or higher, 94% is a solid result for a system of this complexity and maturity. - Connectivity: Near-universal
Because atoms are neutral and movable, any qubit can be brought next to any other qubit. This any-to-any connectivity contrasts with superconducting and silicon platforms, where interactions are largely limited to nearest neighbors.
Scalability and the Road to 2030
Neutral-atom platforms are widely regarded as among the most scalable pathways to fault-tolerant quantum computing.
Unlike superconducting systems, which require massive dilution refrigerators for relatively small numbers of qubits, neutral-atom systems scale by expanding the laser grid itself. More trapping sites mean more qubits—without fundamentally changing the environment.
Rosatom’s public roadmap targets several hundred high-fidelity qubits by 2030. With the three-zone architecture now validated, the central engineering challenge shifts from adding qubits to optimizing the speed and reliability with which atoms can be moved between zones.
The Global Context
This result places the MSU–Rosatom team in direct competition with established neutral-atom leaders such as QuEra and Pasqal.
More importantly, it reinforces a broader trend in quantum development: the race is no longer about raw qubit count alone. Architectural intelligence—how systems manage noise, movement, and modularity—may ultimately matter more than who reaches the next numerical milestone first.
Quantum dominance is no longer a two-horse race. It is a multipolar sprint, and neutral atoms have clearly entered the lead pack.
