The first distributed quantum network of three atomic qubits has been created: a breakthrough towards the quantum internet
An event that can confidently be called historic has occurred in the world of quantum technologies. A research group, combining efforts from Duke University and IonQ, has for the first time successfully created a fully distributed three-node quantum network based on individual atomic qubits. This is not just another laboratory experiment — it is a fundamental step towards the practical implementation of the quantum internet.
The Essence of the Experiment: Entanglement at a Distance
The key result is the formation of a three-party entangled state, known as the Greenberger-Horne-Zeilinger (GHZ) state. In this state, three remote quantum nodes, connected via photonic channels, become inextricably linked: a change in one instantly reflects on all the others, regardless of distance. Previously, such states were achieved only for two nodes or on other physical platforms, but not for individual atomic qubits that can be independently controlled and scaled.
Why This Changes the Game
The main problem with modern quantum computers is scaling. Building one giant quantum processor is incredibly difficult due to error accumulation and physical limitations. The alternative is a modular architecture, where many quantum nodes are connected by photons, forming a distributed computing network. This approach resembles the evolution of the classical internet, where resources are distributed across servers.
In this experiment, researchers not only showed that three atomic memories could "agree" via photonic connections. They achieved high precision: the fidelity of the entangled state was 84–88%. Moreover, for the first time, they managed to fully close the "detection loophole" for a multi-component state and confirm the violation of the Mermin inequality — a strict test for the presence of genuine quantum correlations. This proves that the system operates at a quantum level, not due to random coincidences.
A Step Towards a Commercial Quantum Internet
The work continues a series of breakthroughs by IonQ in the field of photonic connections. Previously, the company demonstrated entanglement of two remote ion systems, and now it has expanded the architecture to three full-fledged nodes. The technology is still far from commercial implementation, but it is precisely such experiments that lay the foundation for distributed quantum computers, secure communication networks, and, in the long term, a global quantum internet.
My Expert Opinion: This experiment is not just a scientific demonstration, but a clear signal to the industry. A modular architecture based on atomic qubits could become the "gold standard" for scaling quantum computing. If the pace of progress continues, we will see the first prototypes of distributed quantum networks for practical tasks within 5–7 years, rather than decades, as previously forecast.