The world's first three-node quantum network: scientists entangled three remote atomic qubits
A team of researchers from Duke University, in collaboration with engineers from IonQ, has achieved a breakthrough in quantum communications: for the first time, they have successfully created a fully distributed three-node quantum network based on individual atomic qubits. During the experiment, a so-called Greenberger-Horne-Zeilinger (GHZ) state was formed, in which three remote quantum nodes become linked via photonic channels.
Quantum entanglement is a fundamental effect where a change in the state of one particle instantly affects others, regardless of the distance between them. Previously, such configurations were only demonstrated for two nodes or on other physical platforms. However, in this case, entanglement was achieved for the first time between three individual atomic qubits that can be independently controlled, read out, and scaled to build computational systems.
Why This Is Crucial
The main challenge for modern quantum computers is scaling. Building a single giant processor involves enormous difficulties due to errors and physical limitations. This is why more and more developers are transitioning to a modular architecture: instead of a monolithic device, a network of many quantum nodes connected by photons is constructed. This approach resembles the evolution of the classical internet, where computing resources are distributed across servers.
The new experiment is a direct step in this direction. The researchers showed 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, the scientists closed the so-called "detection loophole" for a fully distributed multi-component quantum state for the first time. The results also confirmed the violation of the Mermin inequality—one of the strictest tests for the presence of genuine quantum correlations.
The Path to a Quantum Internet
This work continues a series of IonQ studies on photonic quantum connections. Previously, the company demonstrated entanglement between two remote ion systems, and now it has expanded the architecture to three full nodes. Although the technology is still far from commercial application, such experiments are crucial building blocks for future distributed quantum computers, secure communication networks, and ultimately, the quantum internet.
My analysis: Achieving 84–88% fidelity on a three-node network is not just a laboratory curiosity but compelling evidence that a modular architecture based on atomic qubits is viable. Closing the "detection loophole" is particularly important: it eliminates skepticism that the observed effects could be explained by classical correlations. This places distributed quantum computing on a solid physical foundation.