Breakthrough in quantum networks: three-way entanglement of remote atomic qubits achieved for the first time
The world of quantum technologies has taken another significant step forward. A research team from Duke University and IonQ has successfully demonstrated the creation of the first fully distributed three-node quantum network based on individual atomic qubits. The key achievement was the formation of a three-party entangled state, known as the Greenberger-Horne-Zeilinger (GHZ) state, among three remote quantum nodes connected by photonic channels.
The Essence of the Experiment
Quantum entanglement is a phenomenon where multiple particles remain interconnected over any distance, and a change in the state of one is instantly reflected in the others. This property is a cornerstone of future quantum networks and the quantum internet. Previously, scientists had achieved entanglement between two nodes and built three-node networks on other physical platforms. However, our case is unique: for the first time, such a result has been obtained for individual atomic qubits that can be independently controlled, read out, and, critically, scaled to create computing systems.
Why This Is a Breakthrough
The main problem with modern quantum computers is scaling. Building one giant quantum processor is extremely difficult due to error accumulation and hardware limitations. This is why the industry is betting on a modular architecture: instead of a monolithic device, a network of many quantum nodes connected by photons is created. This approach resembles the evolution of the classical internet, where computing resources are distributed across thousands of servers.
Our experiment is a direct step in this direction. We have shown that individual atomic memories can form a shared quantum state through photonic connections while maintaining high operational fidelity. During tests, the fidelity of the entangled state reached 84–88%. Moreover, we have for the first time managed 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 key tests proving the existence of genuine quantum correlations.
The Path to the Quantum Internet
This work continues a series of IonQ's studies on photonic quantum connections. Previously, the company demonstrated entanglement between two remote ion systems, and now we have expanded the architecture to three full-fledged nodes. Although the technology is still far from commercial implementation, such experiments are critically important building blocks for future distributed quantum computers, secure communication networks, and, ultimately, the quantum internet.
Expert Opinion: Achieving three-party entanglement on atomic qubits is not just a laboratory curiosity but a fundamental shift. It proves that modular architecture is viable even at the most complex level — the level of individual atoms. The next logical step is to increase the number of nodes and improve connection fidelity. If the pace of progress continues, the first prototypes of distributed quantum computers could emerge within the next 5–7 years.