For the first time in history: scientists have entangled three remote atomic qubits in a quantum network — a breakthrough toward modular quantum computers
The quantum industry is taking another decisive step toward the practical implementation of distributed computing. A research group, combining efforts from Duke University and IonQ, has announced the creation of the world's first fully distributed three-node quantum network built on individual atomic qubits.
Three-Party Entanglement: A New Quality of Quantum Communication
Specialists have managed to form the so-called Greenberger-Horne-Zeilinger (GHZ) state — a three-party quantum entanglement between three remote nodes connected via photonic channels. Previously, entanglement was successfully demonstrated between two nodes, and three-node networks were created on other physical platforms. However, this result has been achieved for the first time specifically with individual atomic qubits, which can be independently controlled and scaled.
Quantum entanglement is a fundamental effect where multiple particles remain inextricably linked regardless of distance. A change in the state of one particle is instantly reflected in the others. This principle will form the basis of the future quantum internet and secure communications.
Why This Is Crucial for the Industry
The main challenge of modern quantum computers is scaling. Building a single massive quantum processor with millions of qubits is incredibly difficult due to error accumulation and physical limitations. This is why more developers are transitioning to a modular architecture: instead of a monolithic giant, a network of many quantum nodes connected by photonic communication lines is created. This approach resembles the evolution of the classical internet, where computing resources are distributed across thousands of servers.
The new experiment confirms the viability of this strategy. Researchers have shown that individual atomic memories can form a shared quantum state through photonic connections while maintaining high operational accuracy. In the experiment, the fidelity of the entangled state ranged from 84% to 88% — an impressive figure for a three-node system.
Moreover, scientists have for the first time closed the so-called "detection loophole" for a fully distributed multi-component quantum state. Additionally, the results confirmed the violation of the Mermin inequality — one of the key tests proving the presence of genuine quantum correlations rather than classical statistical coincidences.
Looking Ahead: From the Lab to the 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 has now expanded the architecture to three full nodes. Although the technology is still far from commercial application, such experiments are the building blocks of future distributed quantum computers, secure communication networks, and ultimately, the quantum internet.
Expert Opinion: This breakthrough confirms that the modular approach to quantum computing is not just a theory but a working concept. For the crypto industry, this is especially important: distributed quantum networks can provide absolutely secure data transmission, making modern encryption algorithms obsolete. However, practical implementation is still at least 5-7 years away — challenges of scaling and reducing error rates in photonic connections remain to be solved.