Breakthrough in quantum networks: three remote atomic qubits entangled for the first time
The world of quantum technology is taking another significant step forward. A research team, combining efforts from Duke University and IonQ, has successfully implemented three-way quantum entanglement between three remote atomic qubits.
The Essence of the Experiment
In their work, the scientists created a so-called Greenberger-Horne-Zeilinger (GHZ) state — one of the classic examples of multipartite quantum entanglement. Three quantum nodes, physically separated in space, were connected via photonic communication channels. A key feature of the experiment is that this result was achieved for the first time on individual atomic qubits that can be independently controlled and read out.
Why This Is a Turning Point
Previously, entanglement was demonstrated either between two nodes or on other physical platforms. The real breakthrough lies in scaling. The main barrier to building powerful quantum computers is the difficulty of increasing the number of qubits in a single processor due to errors and engineering constraints. A modular architecture, where several small but reliable quantum processors are networked together, is seen as the most promising path forward. This experiment clearly demonstrates that such an architecture is viable.
Key Metrics and Significance
The fidelity of the resulting entangled state was an impressive 84–88%. Moreover, for the first time, researchers managed to close the so-called "detection loophole" for a fully distributed multipartite state. The results also confirmed the violation of the Mermin inequality — a rigorous mathematical test that proves the presence of genuine, rather than classical, quantum correlations.
This is not an isolated success but a continuation of IonQ's systematic work in photonic interconnects. The company had previously demonstrated entanglement between two remote ion systems. Now, the architecture has been expanded to three full nodes, bringing us closer to creating prototypes of distributed quantum computers and the quantum internet.
Analyst's Perspective
From an industry standpoint, this result is more than just a laboratory demonstration. It is a clear signal that the modular approach to quantum computing is moving from the theoretical realm into practice. The ability to link individual atomic qubits with high precision via photonic channels opens the path to creating fault-tolerant networks that could form the basis for secure quantum communication and cloud-based quantum computing. Although commercial implementation is still far off, each such experiment shortens the distance to the quantum internet.