Breakthrough in quantum networks: scientists have entangled three remote atomic qubits for the first time
The world of quantum technologies has taken a significant step forward. A research team combining efforts from Duke University and IonQ has successfully demonstrated the creation of the first fully distributed three-node quantum network based on individual atomic qubits. This experiment marks a new stage in the development of quantum computing architecture.
The Essence of the Experiment
The key achievement was the formation of a so-called three-party entangled state, known as the Greenberger-Horne-Zeilinger (GHZ) state. For the first time, three remote quantum nodes connected via photonic channels were brought into a state where a change in one particle's state instantly affects the other two, regardless of the distance between them.
Previously, similar results were achieved on other physical platforms or with two nodes. However, working specifically with individual atomic qubits, which can be independently controlled, read, and scaled, opens the path to creating full-fledged computing systems.
Why Is This a Breakthrough?
The main problem with modern quantum computers is scaling. Creating one giant quantum processor involves enormous difficulties due to errors and equipment limitations. This is why the industry is increasingly turning to modular architecture. Instead of one giant computer, it proposes building a network of many quantum nodes connected by photons—similar to the development of the classical internet.
This experiment is a practical demonstration of the viability of this approach. The researchers showed that individual atomic memories can form a shared quantum state through photonic connections while maintaining high fidelity of quantum operations.
Key Metrics and Significance
During the experiment, the fidelity of the entangled state reached an impressive 84–88%. Moreover, scientists managed for the first time to close the so-called "detection loophole" for a fully distributed multi-component quantum state. The results also confirmed the violation of the Mermin inequality—one of the most important tests proving the presence of genuine quantum correlations rather than classical ones.
This work continues a series of IonQ studies in the field of photonic quantum connections. Previously, the company demonstrated entanglement between two remote ion systems, and has now successfully expanded the architecture to three full-fledged nodes.
My expert assessment: Although the technology is still far from commercial application, this experiment is a critically important building block for future distributed quantum computers and secure communication networks. We are observing not just a laboratory curiosity, but a purposeful movement toward creating a quantum internet, where computing resources will be distributed as freely as data is today.