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 tripartite entangled state, known as the Greenberger–Horne–Zeilinger state, among three remote quantum nodes connected by photonic channels.
What Happened
Quantum entanglement allows multiple particles to remain connected regardless of the distance between them. A change in the state of one particle instantly affects the state of others, making this effect a cornerstone for future quantum networks and the quantum internet.
Previously, scientists 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, which can be independently controlled, read, and scaled for building computational systems.
Why It Matters
The main challenge of quantum computers is scalability. Building a 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 one giant computer, a network of many quantum nodes connected by photons is created. This approach is reminiscent of the development of the classical internet, where computing resources are distributed among many servers.
The new experiment is a step in this direction. Researchers demonstrated that individual atomic memories could form a shared quantum state through photonic connections while maintaining high accuracy in quantum operations.
During the experiment, the scientists achieved a fidelity of the entangled state at 84–88% and for the first time closed the so-called “detection loophole” for a fully distributed multipartite quantum state. Additionally, the results confirmed the violation of Mermin’s inequality, a key test demonstrating the presence of genuine quantum correlations.
A Step Towards Quantum Internet
The work continues a series of studies by the IonQ team in the field of photonic quantum connections. Previously, the company’s specialists demonstrated entanglement between two remote ion systems, and now they have expanded the architecture to three full-fledged nodes.
Although 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.
