Breakthrough in quantum networks: scientists have entangled three remote atomic qubits for the first time
The world of quantum computing is taking another significant step forward. A team of researchers from Duke University and IonQ has announced the creation of the first fully distributed three-node quantum network built on individual atomic qubits. This event marks a crucial milestone on the path to a practical quantum internet.
The Essence of the Experiment
The work is based on the phenomenon of quantum entanglement — the ability of particles to remain connected at any distance, instantly responding to each other's changes. Scientists managed to form a so-called three-party entangled state (GHZ state) between three remote quantum nodes connected by photonic communication channels. Previously, similar networks have been demonstrated on other physical platforms, but for individual atomic qubits, which can be independently controlled and scaled, this result has been achieved for the first time.
Why This Is Critically Important
The main headache for quantum computer developers is scaling. Creating a single giant quantum processor is incredibly difficult due to error accumulation and physical limitations. This is why the industry is increasingly shifting to a modular architecture: instead of one monolithic device, a network of many quantum nodes connected by photons is built. This approach mirrors the evolution of the classical internet, where computing resources are distributed across thousands of servers.
During the experiment, the researchers demonstrated that individual atomic memories can form a shared quantum state through photonic connections while maintaining high accuracy — the fidelity of the entangled state was an impressive 84–88%. Moreover, the team managed for the first time to close the so-called "detection loophole" for a fully distributed multi-component quantum state, and also recorded a violation of the Mermin inequality — one of the key tests confirming genuine quantum correlations.
A Look to the Future
This work continues a series of IonQ studies on photonic quantum connections. Previously, the company demonstrated entanglement between two remote ion systems, and now it has successfully expanded the architecture to three full nodes. Although commercial application of the technology is still far off, such experiments lay the foundation for future distributed quantum computers, secure communication networks, and ultimately, the quantum internet.
My comment: This experiment is not just an academic victory. It clearly proves that the modular approach to quantum computing is viable. If we can reliably connect individual quantum processors via photonic channels, the scaling problem will cease to be an insurmountable barrier. The industry should closely follow this work: it is precisely these "building blocks" that will become the basis for creating truly powerful quantum networks in the coming years.