Breakthrough in Quantum Networks: Triple entanglement of remote atomic qubits achieved for the first time
Quantum entanglement is a phenomenon where multiple particles remain inextricably linked, regardless of the distance between them. A change in the state of one particle instantly affects the others, making this effect a cornerstone of future quantum networks and the quantum internet. Until recently, demonstrations of entanglement were limited to two nodes, but we have now witnessed a significant step forward.
What happened
Researchers from Duke University and IonQ announced the creation of the first fully distributed three-node quantum network based on individual atomic qubits. For the first time in history, they managed to form a three-party entangled state, known as the Greenberger-Horne-Zeilinger (GHZ) state, between three remote quantum nodes connected by photonic channels. It is important to note that similar results have been achieved before on other physical platforms, but this is the first instance for individual atomic qubits that can be independently controlled, read out, and scaled.
Why this matters
The main challenge of modern quantum computers is scaling. Building one giant quantum processor is extremely difficult due to errors and hardware limitations. That is why many developers are betting on a modular architecture: instead of one giant computer, a network of many quantum nodes connected by photons is created. This approach resembles the development of the classical internet, where computing resources are distributed across many servers.
The new experiment is a direct step in this direction. The researchers demonstrated that individual atomic memories can form a shared quantum state through photonic connections while maintaining high fidelity of quantum operations. The achieved fidelity of the entangled state was 84–88%. Moreover, for the first time, the so-called "detection loophole" was closed for a fully distributed multi-component quantum state, and the results confirmed the violation of the Mermin inequality — one of the key tests proving the existence of genuine quantum correlations.
A step towards the quantum internet
This 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.
Expert commentary: This breakthrough is not just an academic achievement. It proves that the modular approach to building quantum systems is viable. The ability to connect individual atomic qubits into a network with high precision paves the way for creating scalable quantum computers that can solve problems inaccessible to classical machines. For cryptocurrencies and blockchain, this means a potential threat to current cryptographic standards, but also an opportunity for developing quantum-resistant algorithms.