Breakthrough in quantum networks: scientists have entangled three remote atomic qubits for the first time
A group of researchers from Duke University and the company IonQ has taken a significant step toward creating a quantum internet. In an experiment, they managed to form a three-way entangled state (Greenberger-Horne-Zeilinger state, GHZ) between three remote quantum nodes connected by photonic channels. This is the first successful achievement of this kind for individual atomic qubits, which fundamentally distinguishes this work from previous experiments on other physical platforms.
What happened and why it matters
Quantum entanglement is a fundamental phenomenon in which multiple particles remain inextricably linked, regardless of distance. A change in the state of one instantly affects the others, making this effect the foundation for future quantum networks. Previously, scientists demonstrated entanglement between two nodes, but creating a full-fledged three-node network on atomic qubits is an entirely new level of complexity. The key advantage of the atomic qubits used in IonQ lies in the ability to independently control, read out, and scale them for building computational systems.
Modular architecture: the future of quantum computing
The main problem with modern quantum computers is scaling. Building one giant processor is extremely difficult due to error accumulation and hardware limitations. A modular architecture, where instead of one large computer, a network of many quantum nodes connected by photons is created, is considered the most promising solution. This approach resembles the development of the classical internet, where computing resources are distributed among servers.
The new experiment clearly demonstrates that individual atomic memories can form a shared quantum state through photonic connections while maintaining high operational accuracy. During tests, the fidelity of the entangled state was 84–88%. Furthermore, scientists managed for the first time to close the so-called "detection loophole" for a fully distributed multi-component quantum state. The results also confirmed the violation of the Mermin inequality, one of the key tests proving the presence of genuine quantum correlations.
A step toward the quantum internet
The work continues a series of studies by the IonQ team in the field of photonic quantum connections. Previously, they 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 critically important building blocks for future distributed quantum computers, secure communication networks, and the quantum internet.
My comment as an analyst: This experiment is not just an academic achievement. It paves the way for the practical implementation of modular quantum processors that can solve problems inaccessible to classical supercomputers. The combination of atomic qubits and photonic channels looks particularly promising for creating robust and scalable quantum networks.