Researchers from Duke University and IonQ have announced the creation of the first fully distributed three-node quantum network based on individual atomic qubits, according to Quantum Computing Report.
The team successfully formed a so-called tripartite entangled state (Greenberger–Horne–Zeilinger state) among three remote quantum nodes connected by photonic channels.
Source: Quantum Computing Report.What Happened
Quantum entanglement allows multiple particles to remain interconnected regardless of the distance separating them. A change in the state of one particle is instantly reflected in the states of the others, making this effect fundamental for future quantum networks and the quantum internet.
Previously, scientists had demonstrated entanglement between two remote quantum nodes and even three-node networks on other physical platforms. However, this is the first time such a result has been achieved with individual atomic qubits that can be independently controlled, read, and scaled for computational systems.
Why It Matters
The main challenge for quantum computers is scaling. Building a single large quantum processor is extremely difficult due to errors and hardware limitations.
As a result, many developers are focusing on a modular architecture: instead of a single massive computer, a network of multiple quantum nodes connected by photons is created. This approach is reminiscent of the development of the classical internet, where computational resources are distributed across numerous servers.
The new experiment represents a step in this direction. Researchers demonstrated that individual atomic memories can form a shared quantum state through photonic connections while maintaining high fidelity in quantum operations.
During the experiment, the team achieved a fidelity of the entangled state between 84% and 88% and successfully closed what is known as the "detection loophole" for a fully distributed multi-component quantum state for the first time. Additionally, the results confirmed the violation of the Mermin inequality—one of the key tests demonstrating the presence of genuine quantum correlations.
A Step Toward the Quantum Internet
This work continues IonQ's series of 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.
While the technology is still far from commercial application, such experiments are considered important building blocks for future distributed quantum computers, secure communication networks, and the quantum internet.
In June, Colt Technology Services and Ciena successfully tested data transmission with quantum-resistant encryption between New York and London.