Scientists build an evolutionary network node with light and ions

The new interface opens the way to the connection of quantum devices.

Quantum networks are often described as the next internet step. Instead of transferring ordinary digital information to bits, they use photons to transport quantum information. This approach could make communication practically unbreakable, connect distant quantum computers into a powerful system and allow detection technologies capable of measuring time and environmental conditions with extraordinary precision.

For this type of network, researchers must develop quantum network nodes which can both store quantum information and exchange it via light particles. In a recent breakthrough, a team led by Ben Lanyon in the Department of Experimental Physics at the University of Innsbruck, has demonstrated such a node using a chain of ten calcium ions inside a quantum computer prototype.

By finely controlling the electric fields, scientists have guided the ions one both in an optical cavity. Inside the cavity, a carefully calibrated laser pulse made each ion emit photonWith the polarization of the photon entangled with the quantum state of the ion.

Link ions and photons

The process has created a flow of photons; Everyone linked to a different ion qubit in the register. In the future, photons could move to distant nodes and be used to establish a tangle between separate quantum devices. The researchers obtained an average fidelity in Ion-Photon intrigue of 92%, a level of precision which underlines the robustness of their method.

“One of the main forces of this technique is its scalability,” says Ben Lanyon. “While previous experiences have managed to bind only two or three ionic qubits to individual photons, the innsbruck configuration can be extended to much more important registers, potentially containing hundreds of ions and more.” This opens the way to the connection of whole quantum processors between laboratories or even continents.

“Our method is a step towards the construction of larger and more complex quantum networks,” explains Marco Canteri, the first author of the study. “This brings us closer to practical applications such as quantum-security communication, distributed quantum calculationand quantum detection distributed on a large scale. »»

Wider applications

Beyond networking, technology could also advance optical atomic clocks, which keep time so precisely that they would waste less than a second on the age of the universe. These clocks could be linked via quantum networks to form a global system of timing without correspondence precision.

Reference: “Register of ten interfaced qubit to photons of trapped ions” by Mr. Canteri, ZX Koong, J. Bate, A. Winkler, V. Krutyanskiy and BP Lanyon, August 21, 2025, Physical examination letters.
Two: 10.1103 / V5K1-Whwz

The work has been financially supported by the Austrian Sciences Fund FWF and the European Union, among others, and demonstrate not only a technical step, but also a key construction element for the next generation of quantum technologies.

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