Breakthrough in Quantum Networks: Scientists Create Three-Way Entanglement on Remote Atomic Qubits for the First Time
A team of researchers from Duke University and IonQ has made a significant step in the development of quantum technologies. They have successfully demonstrated the world's first fully distributed three-node quantum network built on individual atomic qubits. This event marks an important milestone on the path to creating a quantum internet and scalable quantum computing systems.
The Essence of the Experiment
The work is based on creating a so-called Greenberger-Horne-Zeilinger (GHZ) state—a three-party quantum entanglement. In this state, three remote quantum nodes connected by photonic channels form a single quantum system. A change in the state of one qubit is instantly reflected in the other two, regardless of the distance between them.
Previously, similar results were achieved on other physical platforms or with two nodes. However, in this case, three-node entanglement has been realized for the first time specifically on individual atomic qubits. The key advantage of this approach is the ability for independent control, readout, and, critically, scaling the system to build full-fledged computing machines.
Why This Matters for the Industry
The main barrier to creating powerful quantum computers is scaling. Building one giant quantum processor is extremely difficult due to error accumulation and physical limitations. That is why more and more developers are transitioning to a modular architecture. Instead of one huge device, a network of many quantum nodes connected by photons is created. This resembles the evolution of the classical internet, where resources are distributed among servers.
The new experiment is direct proof of the viability of this concept. The researchers showed that individual atomic memories can form a common quantum state through photonic connections while maintaining high operational accuracy. The fidelity of the resulting entangled state was 84–88%. Moreover, for the first time, scientists managed to close the "detection loophole" for a fully distributed multi-component quantum state and confirm the violation of the Mermin inequality—a strict test for the presence of genuine quantum correlations.
Looking to the Future
This work continues a series of IonQ studies in the field of photonic quantum connections. Previously, the company demonstrated entanglement between two remote ion systems, and has now expanded the architecture to three full-fledged nodes. Although the technology is still far from commercial implementation, such experiments are fundamental building blocks for future distributed quantum computers, secure communication networks, and, ultimately, the quantum internet.
Expert Opinion: This result is not just a laboratory victory. It proves that the modular approach to quantum computing is technically feasible. For the crypto industry, this is a signal: data protection using quantum key distribution (QKD) within such networks could become a reality sooner than the emergence of a full-fledged quantum computer capable of breaking existing encryption algorithms.