Breakthrough in quantum networks: three-way entanglement of remote atomic qubits achieved for the first time
The world of quantum computing is taking another significant step forward. A research team from Duke University and IonQ has announced the creation of the first fully distributed three-node quantum network based on individual atomic qubits. This achievement marks a crucial milestone on the path to the practical realization of a quantum internet.
The key result of the experiment was the formation of the so-called Greenberger-Horne-Zeilinger (GHZ) state among three remote quantum nodes. The GHZ state is a classic example of multipartite quantum entanglement, where a change in the state of one particle instantly affects all others, regardless of distance. Previously, similar networks have been demonstrated on other physical platforms, but this is the first time such a result has been achieved specifically for individual atomic qubits that can be independently controlled, read out, and scaled.
Why This Is Fundamentally Important
The main problem with modern quantum computers is scaling. Building a single, giant, error-free quantum processor is incredibly difficult. This is precisely why the industry is betting on a modular architecture: instead of a monolithic device, a network of many quantum nodes connected by photonic channels is created. This approach is completely analogous to how the classical internet developed, where computing power is distributed among servers.
The new experiment is a direct step in this direction. The researchers convincingly demonstrated that individual atomic memory cells can form a unified quantum state through photonic connections while maintaining high operational fidelity. The fidelity of the resulting entangled state was an impressive 84–88%. Moreover, for the first time for a fully distributed multi-component quantum state, the so-called "detection loophole" was closed, and the results confirmed the violation of the Mermin inequality — a rigorous test for the presence of genuine quantum correlations, excluding classical explanations.
Architecture of the Future
This work continues a series of IonQ studies in the field of photonic quantum connections. Previously, the team demonstrated entanglement between two remote ion systems, and now they have successfully expanded the architecture to three full-fledged nodes. Although the technology is still at the stage of laboratory prototypes and far from commercial application, it is precisely such experiments that are critically important building blocks for future distributed quantum computers and secure communication networks.
Expert opinion: This breakthrough is not just a laboratory curiosity. The demonstration of three-way entanglement on atomic qubits with high fidelity and the closing of detection loopholes directly brings us closer to creating fault-tolerant quantum networks. It proves that the modular approach is viable, and we can expect the first prototypes of a quantum internet within the next 5-7 years, rather than decades.