A rudimentary quantum network link between Dutch cities
News - 31 October 2024 - Webredactie Communication
An international research team led by QuTech has demonstrated a network connection between quantum processors over metropolitan distances. Their result marks a key advance from early research networks in the lab towards a future quantum internet. The team developed fully independently operating nodes and integrated these with deployed optical internet fibre, enabling a 25 km quantum link. The researchers published their findings in Science Advances.

The internet allows people to share information (bits) globally. A future quantum internet will enable sharing quantum information (qubits) over a new type of network. Such qubits can not only take the values 0 or 1, but also superpositions of those (0 and 1 at the same time). In addition, qubits can be entangled, which means they share a quantum connection enabling instant correlations, no matter the distance.

Researchers around the globe are working to build quantum networks that make use of these features to offer fundamentally new communication and computing capabilities, in coexistence with the current internet. For example, qubits can generate secure encryption keys for safely sharing financial or medical data. Quantum links can also connect distant quantum computers, enhancing their power and allowing access with full privacy for users.

Moving out of the lab
An international team led by Ronald Hanson at QuTech—a collaboration between the TU Delft and TNO—was able to connect two small quantum computers between the Dutch cities of Delft and The Hague. “The distance over which we create quantum entanglement in this project, via 25 km of deployed underground fiber, is a record for quantum processors,” says Hanson. “This is the first time such quantum processors in different cities are connected.”

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