Breakthrough in quantum networks: three-way entanglement of remote atomic qubits achieved for the first time
A team of researchers from Duke University and IonQ has made a significant step in the development of distributed quantum computing. For the first time in history, they have managed to create a fully functioning three-node quantum network based on individual atomic qubits connected via photonic channels. The key achievement was the formation of the so-called Greenberger-Horne-Zeilinger (GHZ) state — a three-way quantum entanglement between remote nodes.
What This Means for the Quantum Industry
Quantum entanglement is a phenomenon where the state of one particle instantly influences the state of another, regardless of the distance between them. Previously, scientists demonstrated entanglement between two qubits and even built three-node networks on other physical platforms, but it is atomic qubits, which can be independently controlled and read out, that are of greatest interest for creating scalable computing systems.
The main problem with modern quantum computers is scaling. Building a single large quantum processor with a low error rate is extremely difficult. Therefore, the industry is moving toward a modular architecture: instead of a monolithic chip, a network of many quantum nodes connected by photons is created. This approach resembles the evolution of the classical internet, where computing power is distributed across thousands of servers.
Technical Details of the Experiment
During the experiment, the researchers achieved an entangled state fidelity of 84–88%. This is an outstanding figure for a distributed system. Moreover, the 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 strictest tests for the presence of genuine quantum correlations.
The work continues a series of IonQ studies on photonic connections. Previously, the company demonstrated entanglement between two remote ion systems, and now it has successfully expanded the architecture to three full-fledged nodes.
My analysis: Although the commercial application of this technology is still far off, this experiment is an ideal building block for the future quantum internet. The ability to link individual atomic qubits into a distributed network without losing the quality of quantum operations opens the path to creating fault-tolerant quantum computers and absolutely secure communication channels. This is precisely the foundation on which the next generation of computing infrastructure will be built.